Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

St. John's Wort 300 mg Ingredients & Drug Interactions

by Nature's Way

Capsule Category: Botanical
Most serious interaction: Major
The interaction bottom line Most serious interaction: Major

St. John's Wort 300 mg is a dietary supplement by Nature's Way with 3 active ingredients. Its ingredients are commonly taken for general nutrition and energy, antioxidant support, cholesterol and metabolic health.Based on those ingredients, 1,347 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are St. John's Wort Flower, Leaf, Stem Extract, Rosemary, Spirulina. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of St. John's Wort 300 mg by Nature's Way

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 3 of its 3 active ingredients.
  • “St. John's Wort Flower, Leaf, Stem Extract” is listed as a grouped ingredient — the label gives one combined amount (300 mg) without saying how much of each component you get.

This product contains 3 active ingredients. Spirulina is a blue-green algae that's been used for nutritional support.

Rosemary is a culinary herb included here for its traditional uses. The main active ingredient is St.

John's Wort flower, leaf, and stem extract — the traditional botanical used in herbal medicine — though we hold the data as a group and cannot break down its individual components. The capsule also contains inactive ingredients: hypromellose, cellulose, and magnesium stearate (standard fillers and binders).

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use.

Why this rating?
  • The label markets this product for: promotes positive mood and brighter outlook.
  • We looked for evidence on: Anxiety, Depression, Seasonal affective disorder (SAD), Stress, Social anxiety disorder, mood support — and 1 related terms.
  • The closest evidence on file: Rosemary is rated "Insufficient Reliable Evidence To Rate" for Depression (Natural Medicines).
  • Also on file: Rosemary is rated "Insufficient Reliable Evidence To Rate" for Stress.
  • Also on file: Blue-green Algae is rated "Insufficient Reliable Evidence To Rate" for Anxiety, Depression, Stress.

For spirulina, the data shows it's possibly effective for high blood pressure (hypertension). For acne, iron deficiency anemia, and allergic rhinitis (hay fever), the evidence is insufficient to rate.

For rosemary, it's possibly effective for memory support. Age-related cognitive decline, alopecia areata, and nonalcoholic fatty liver disease show insufficient evidence.

We don't hold effectiveness data for the St. John's Wort extract component or dianthrones.

The evidence, ingredient by ingredient Blue-green Algae Rosemary St. John's Wort

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 2 of the 2 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 2 of 2.
  • General safety write-ups exist for 2 of 2.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Spirulina is generally well tolerated orally, though some people experience abdominal cramps, bloating, diarrhea, dizziness, fatigue, flatulence, headache, nausea, or vomiting. Rarely, allergic reactions including rashes, itching, or even anaphylaxis have occurred — if you develop lip swelling, breathing difficulty, or hives, seek immediate care.

A small number of people taking spirulina reported mild gum bleeding or bruising. Rosemary in food amounts is safe, but medicinal doses during pregnancy should be avoided due to insufficient safety data.

Topically, it can cause allergic contact dermatitis or photosensitivity in some people. Orally, undiluted rosemary oil or its camphor content might trigger seizures.

Quality varies across spirulina products and some can be contaminated with toxins or heavy metals — check your source carefully.

Side effects, ingredient by ingredient Blue-green Algae Rosemary St. John's Wort

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 2 of the 2 matched ingredients can interact with medications — Rosemary, Blue-green Algae.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications.
  • For scale: 490 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Check your medications before using this product if you take anticoagulants or antiplatelet drugs (blood thinners or aspirin-type drugs) — moderate risk of increased bleeding. Also flag it if you use antidiabetes drugs, immunosuppressants, or salicylate-containing pain relievers.

Additionally, mention it if you take medications processed through the CYP1A2 enzyme, as rosemary may lower their levels.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Moderate medication interactions have been identified, and safety information is well characterized.

If you take any blood thinners, diabetes medications, immune-suppressing drugs, or salicylate-containing pain relievers, you'll want to check this product against your exact medications before starting. Spirulina products vary widely in purity, so source matters.

Talk to your pharmacist or doctor about whether this product fits your health needs and current medications.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 2 of 3 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated May 21, 2025.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about St. John's Wort 300 mg, straight from the product label.

Brand Nature's Way
Barcode (UPC) 033674630006
Net contents 90 Vegan Capsule(s)
Market status On market
Date entered into DSLD May 21, 2025
DSLD ID 333772
Product type Botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Women (not pregnant or lactating), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for St. John's Wort 300 mg by Nature's Way, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
90
UPC/BARCODE
033674630006
IngredientAmount% DV
Spirulina40 mg--
Rosemary80 mg--
St. John's Wort Flower, Leaf, Stem Extract300 mg--
Dianthrones0.45 mg--

Other ingredients: Hypromellose, Cellulose, Magnesium Stearate

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Formulation

Promotes a Positive Mood Helps support a brighter outlook Botanicals are sourced where they grow best Made with the quality you trust

Gluten free. No wheat, corn, soy, dairy, gelatin, or artificial colors or flavors.

Bottled and tested in the USA

Vegan Gelatin Free

Vegan Gelatin Free

Promotes a positive mood Plant powered

Non GMO Project Verified nongmoproject.org

General Statements

Explore more products at NATURESWAY.COM

50% Bottle made from 50% post-consumer recycled plastic

Precautions

Keep out of reach of children.

Safety sealed with inner seal. Do not use if seal is broken or missing.

Warning: Do not use if you are pregnant or nursing. St. John's Wort has the potential to interact with many prescription drugs, including oral contraceptives and antidepressants. If you are taking any medications or planning surgery, consult a healthcare professional before use.

Avoid excessive exposure to UV radiation (e.g., sunlight or tanning) while using this product.

Storage

Keep tightly closed. Store at room temperature. Avoid excessive heat and direct sunlight.

Brand IP Statement(s)

Copyright 2024 Nature’s Way Brands, LLC

Seals/Symbols

Vegan Gelatin Free

Non GMO Project Verified nongmoproject.org

FDA Disclaimer Statement

These statements have not been evaluated by the Food & Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Formula

St. John's Wort Premium Extract 300 mg Extract per serving

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Recommendation: Adults take 1 capsule two to three times daily, preferably with food. Best results obtained with continuous use.

See for yourself

St. John's Wort 300 mg by Nature's Way label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in St. John's Wort 300 mg by Nature's Way

These are the 3 active ingredients this product is made of. Select any to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Servings per container90 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Spirulina

Interacts with
327 drugs
40 mg per serving

Blue-green algae are nutrient-rich aquatic microorganisms (such as spirulina and Klamath Lake algae) taken as a supplement for energy, nutrition, and...

Spirulina monograph & interactions

Rosemary

Interacts with
372 drugs
80 mg per serving

Rosemary is a fragrant Mediterranean herb that is safe and flavorful in normal food amounts. Some early research suggests possible benefits for memory...

Rosemary monograph & interactions

St. John's Wort Flower, Leaf, Stem Extract

Interacts with
1,143 drugs
300 mg per serving Form: St. John's Wort Flower Extract, St. John's Wort Leaf Extract, St. John's Wort Stem Extract

St. John's wort is a well-studied herb most often used for mild to moderate depression, and some research suggests it may help with this. However, it...

St. John's Wort Flower, Leaf, Stem Extract monograph & interactions
  • › Dianthrones

Other (inactive) ingredients: Hypromellose, Cellulose, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

St. John's Wort 300 mg by Nature's Way Drug Interactions

Want to check YOUR meds against St. John's Wort 300 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
1,347Drugs
755 Major 592 Moderate

Ingredients driving the most interactions

Rosemary 372
Spirulina 327

Each ingredient & the kinds of drugs it affects

For each ingredient in St. John's Wort 300 mg with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

St. John's Wort Flower, Leaf, Stem Extract47 drug types · 1,143 drugs

Alprazolam (Xanax)

St. John's wort increases the clearance of alprazolam and decreases its effects.
Alprazolam, which is used as a probe for cytochrome P450 3A4 (CYP3A4) activity, has a two-fold increase in clearance when given with St. John's wort. St. John's wort reduces the half-life of alprazolam from 12.4 hours to 6 hours.

Likelihood Likely Evidence B
Contraceptive Drugs

St. John's wort increases the clearance of contraceptive drugs and reduces their clinical effects.
Females taking St. John's wort and oral contraceptives concurrently should use an additional or alternative form of birth control. St. John's wort can decrease norethindrone and ethinyl estradiol levels by 13% to 15%, resulting in breakthrough bleeding, irregular menstrual bleeding, or unplanned pregnancy. Bleeding irregularities usually occur within a week of starting St. John's wort and regular cycles usually return when St. John's wort is discontinued. Unplanned pregnancy has occurred with concurrent use of oral contraceptives and St. John's wort extract. St. John's wort is thought to induce the cytochrome P450 1A2 (CYP1A2), 2C9 (CYP2C9), and 3A4 (CYP3A4) enzymes, which are responsible for metabolism of progestins and estrogens in contraceptives.

Likelihood Probable Evidence B
Cyclosporine (Neoral, Sandimmune)

St. John's wort reduces the levels and clinical effects of cyclosporine.
Concomitant use can decrease plasma cyclosporine levels by 30% to 70%. Using St. John's wort with cyclosporine in patients with heart, kidney, or liver transplants can cause subtherapeutic cyclosporine levels and acute transplant rejection. This interaction has occurred with a St. John's wort extract standardized to 0.3% hypericin and dosed at 300-600 mg per day. Withdrawal of St. John's wort can result in a 64% increase in cyclosporine levels. St. John's wort induces cytochrome P450 3A4 (CYP3A4) and the multi-drug transporter, P-glycoprotein/MDR-1, which increases cyclosporine clearance.

Likelihood Probable Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

St. John's wort increases the metabolism and reduces the levels of CYP3A4 substrates.
St. John's wort induces CYP3A4 enzymes and increases metabolism of CYP3A4 substrates. Clinically significant interactions have been reported with St. John's wort products containing hyperforin 1 mg or more.

Likelihood Probable Evidence B
Digoxin (Lanoxin)

St. John's wort reduces the levels and clinical effects of digoxin.
St. John's wort can reduce the bioavailability, serum levels, and therapeutic effects of digoxin. Taking an extract of St. John's wort 900 mg, containing hyperforin 7.5 mg or more, daily for 10-14 days, can reduce serum digoxin levels by 25% in healthy people. St. John's wort is thought to affect the multidrug transporter, P-glycoprotein, which mediates the absorption and elimination of digoxin and other drugs. St. John's wort products providing less than 7.5 mg of hyperforin daily do not appear to affect digoxin levels.

Likelihood Likely Evidence B
Docetaxel (Taxotere)

St. John's wort reduces the levels and clinical effects of docetaxel.
Clinical research shows that taking a specific St. John's wort product (Hyperiplant, VSM) 300 mg three times daily for 14 days increases docetaxel clearance by about 14%, resulting in decreased plasma concentrations of docetaxel in cancer patients. This is most likely due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort.

Likelihood Probable Evidence B
Imatinib (Gleevec)

St. John's wort reduces the levels and clinical effects of imatinib.
Taking St. John's wort 900 mg daily for 2 weeks reduces the bioavailability and half-life of a single dose of imatinib and decreases its serum levels by 30% in healthy volunteers. This is most likely due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort, which increases clearance of imatinib.

Likelihood Likely Evidence A
Irinotecan (Camptosar)

St. John's wort reduces the levels and clinical effects of irinotecan.
St. John's wort 900 mg daily for 18 days decreases serum levels of irinotecan by at least 50%. Clearance of the active metabolite of irinotecan, SN-38, is also increased, resulting in a 42% decrease in the area under the concentration-time curve. This is thought to be due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort.

Likelihood Likely Evidence A
Mephenytoin (Mesantoin)

St. John's wort reduces the levels and clinical effects of mephenytoin.
Preliminary clinical research in healthy males shows that taking St. John's wort for 14 days induces cytochrome P450 2C19 (CYP2C19) and significantly increases metabolism of mephenytoin (Mesantoin). In people with wild-type 2C19, metabolism was almost 4-fold greater in subjects who received St. John's wort compared to placebo. In contrast, patients with 2C19*2/*2 and *2/*3 genotypes did not demonstrate a similar increase in metabolism.

Likelihood Likely Evidence B
Non-Nucleoside Reverse Transcriptase Inhibitors (Nnrtis)

St. John's wort decreases the levels and clinical effects of NNRTIs.
St. John's wort increases the oral clearance of nevirapine (Viramune) by 35%. Subtherapeutic concentrations are associated with therapeutic failure, development of viral resistance, and development of drug class resistance. St. John's wort induces intestinal and hepatic cytochrome P450 3A4 (CYP3A4) and intestinal P-glycoprotein/MDR-1, a drug transporter.

Likelihood Likely Evidence B
Omeprazole (Prilosec)

St. John's wort decreases the levels and clinical effects of omeprazole.
Taking St. John's wort, 300 mg orally three times daily for 14 days, reduces serum concentrations of omeprazole by inducing its metabolism via cytochrome P450 (CYP) 2C19 and 3A4. The reduction of omeprazole serum levels is dependent on CYP2C19 genotype, with reductions up to 50% in extensive metabolizers and 38% in poor metabolizers.

Likelihood Likely Evidence B
Oxycodone (Oxycontin)

St. John's wort decreases the levels and clinical effects of oxycodone.
St. John's wort can increase oxycodone metabolism by inducing cytochrome P450 3A4 (CYP3A4), reducing plasma levels and analgesic activity.

Likelihood Probable Evidence B
P-Glycoprotein Substrates

St. John's wort decreases the levels and clinical effects of P-glycoprotein substrates.
St. John's wort induces P-glycoprotein. P-glycoprotein is a carrier mechanism responsible for transporting drugs and other substances across cell membranes. When P-glycoprotein is induced in the gastrointestinal (GI) tract, it can prevent the absorption of some medications. In addition, induction of p-glycoprotein can decrease entry of drugs into the central nervous system (CNS) and decrease access to other sites of action.

Likelihood Probable Evidence B
Phenobarbital (Luminal)

St. John's wort decreases the levels and clinical effects of phenobarbital.
St. John's wort may increase the metabolism of phenobarbital. Plasma concentrations of phenobarbital should be monitored carefully. The dose of phenobarbital may need to be increased when St. John's wort is started and decreased when it is stopped.

Likelihood Likely Evidence B
Phenprocoumon (Marcoumar, Others)

St. John's wort decreases the levels and clinical effects of phenprocoumon.
St. John's wort appears to increase the metabolism of phenprocoumon (an anticoagulant that is not available in the US) by increasing the activity of the cytochrome P450 2C9 (CYP2C9) enzyme. This may result in decreases in the anticoagulant effect and international normalized ratio (INR).

Likelihood Likely Evidence B
Phenytoin (Dilantin)

St. John's wort decreases the levels and clinical effects of phenytoin.
St. John's wort may increase the metabolism of phenytoin. Plasma concentrations of phenytoin should be monitored closely. The dose of phenytoin may need to be increased when St. John's wort is started and decreased when it is stopped.

Likelihood Likely Evidence B
Protease Inhibitors (Pis)

St. John's wort reduces the levels and clinical effects of PIs.
In healthy volunteers, St. John's wort can reduce the plasma concentrations of indinavir (Crixivan) by inducing cytochrome P450 3A4 (CYP3A4). This might result in treatment failure and viral resistance. St. John's wort also induces P-glycoprotein, which can result in decreased intracellular protease inhibitor concentrations and increased elimination.

Likelihood Likely Evidence B
Rivaroxaban (Xarelto)

St. John's wort decreases the levels and clinical effects of rivaroxaban.
A small pharmacokinetic study in healthy volunteers shows that taking a single dose of rivaroxaban 20 mg after using a specific St. John's wort extract (Jarsin, Vifor SA) 450 mg orally twice daily for 14 days reduces the bioavailability of rivaroxaban by 24% and reduces rivaroxaban's therapeutic inhibition of factor Xa by 20%.

Likelihood Probable Evidence B
Tacrolimus (Prograf)

St. John's wort decreases the levels and clinical effects of tacrolimus.
Taking a St. John's wort extract (Jarsin) 600 mg daily significantly decreases tacrolimus serum levels. Dose increases of 60% may be required to maintain therapeutic tacrolimus levels in patients taking St. John's wort. St. John's wort is thought to lower tacrolimus levels by inducing cytochrome P450 3A4 (CYP3A4) enzymes. A small clinical study in healthy adults also shows that taking St. John's wort 300 mg three times daily for 10 days decreases the total systemic exposure to tacrolimus by 27% and 33% after taking a single 5 mg dose of immediate-release or prolonged-release tacrolimus, respectively.

Likelihood Likely Evidence B
Warfarin (Coumadin)

St. John's wort decreases the levels and clinical effects of warfarin.
Taking St. John's wort significantly increases clearance of warfarin, including both its R- and S-isomers. This is likely due to induction of cytochrome P450 (CYP) 1A2 and CYP3A4. St. John's wort can also significantly decrease International Normalized Ratio (INR) in people taking warfarin. In addition, taking warfarin at the same time as St. John's wort might reduce warfarin bioavailability. When a dried extract is mixed with warfarin in an aqueous medium, up to 30% of warfarin is bound to particles, reducing its absorption.

Likelihood Likely Evidence B
Aminolevulinic Acid

St. John's wort might have additive phototoxic effects with aminolevulinic acid.
Concomitant use with St. John's wort extract may cause synergistic phototoxicity. Delta-aminolevulinic acid can cause a burning erythematous rash and severe swelling of the face, neck, and hands when taken with St. John's wort.

Likelihood Possible Evidence D
Bupropion (Wellbutrin)

St. John's wort might reduce the levels and effects of bupropion.
Clinical research shows that taking St. John's wort 325 mg three times daily for 14 days along with bupropion reduces the area under the concentration-time curve by approximately 14% and increases the clearance of bupropion by approximately 20%. This effect is attributed to the induction of cytochrome P450 2B6 (CYP2B6) by St. John's wort.

Likelihood Probable Evidence B
Clopidogrel (Plavix)

St. John's wort might increase the levels and effects of clopidogrel.
Taking St. John's wort with clopidogrel seems to increase the activity of clopidogrel. In clopidogrel non-responders, taking St. John's wort seems to induce metabolism of clopidogrel to its active metabolite by cytochrome P450 enzymes 3A4 and 2C19. This leads to increased antiplatelet activity. Theoretically, this might lead to an increased risk of bleeding in clopidogrel responders.

Likelihood Possible Evidence B
Clozapine (Clozaril)

St. John's wort might decrease the levels and clinical effects of clozapine.
A case report describes a female with schizophrenia controlled on clozapine who had a return of symptoms when she started taking St. John's wort. The plasma concentration of clozapine was reduced, likely because its clearance was increased due to induction of the cytochrome P450 enzymes 3A4, 1A2, 2C9, and 2C19 by St. John's wort.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

St. John's wort may increase the metabolism and reduce the levels of CYP1A2 substrates.
Clinical and in vitro research shows that St. John's wort induces CYP1A2, but to a lesser extent than CYP3A4.

Likelihood Possible Evidence B

Rosemary6 drug types · 372 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, rosemary may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.
In vitro and animal research suggests that rosemary inhibits platelet aggregation.

Likelihood Possible Evidence D
Antidiabetes Drugs

Theoretically, taking rosemary with antidiabetes drugs might increase the risk of hypoglycemia.
Animal research shows that rosemary extract can decrease blood glucose levels in diabetic models. However, research in humans is conflicting. Although rosemary powder decreased blood glucose levels in healthy adults, no change in blood glucose levels was seen in adults with type 2 diabetes, most of whom were taking antidiabetes drugs.

Likelihood Possible Evidence B
Aspirin

Theoretically, rosemary might have additive effects with salicylate-containing drugs such as aspirin.
Rosemary is reported to contain salicylates.

Likelihood Possible Evidence D
Choline Magnesium Trisalicylate (Trilisate)

Theoretically, rosemary might have additive effects with salicylate-containing drugs such as choline magnesium trisalicylate.
Rosemary is reported to contain salicylate.

Likelihood Possible Evidence D
Salsalate (Disalcid)

Theoretically, rosemary might have additive effects with salicylate-containing drugs such as salsalate.
Rosemary is reported to contain salicylate.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

Theoretically, rosemary might decrease the levels and clinical effects of CYP1A2 substrates.
In vitro research shows that rosemary induces CYP1A2 enzymes. This effect has not been reported in humans.

Likelihood Unlikely Evidence D

Spirulina3 drug types · 327 drugs

Anticoagulant/Antiplatelet Drugs

Theoretically, spirulina blue-green algae might increase the risk of bleeding if used with other anticoagulant or antiplatelet drugs. However, this is unlikely.
Spirulina blue-green algae have shown antiplatelet and anticoagulant effects in vitro. However, one preliminary study in 24 patients receiving spirulina blue-green algae 2.3 grams daily for 2 weeks showed no effect on platelet activation or measures of clotting time.

Likelihood Unlikely Evidence D
Antidiabetes Drugs

Theoretically, taking blue-green algae with antidiabetes drugs might increase the risk of hypoglycemia.
Human research shows that spirulina blue-green algae can have hypoglycemic effects in patients with diabetes, at least some of whom were using antidiabetes drugs. However, blue-green algae does not seem to improve glycated hemoglobin (HbA1c) levels in patients with diabetes. A meta-analysis of animal studies also suggests that spirulina blue-green algae have hypoglycemic effects.

Likelihood Possible Evidence B
Immunosuppressants

Theoretically, concurrent use of blue-green algae might interfere with immunosuppressive therapy.
Blue-green algae have been shown to stimulate the immune system.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for St. John's Wort 300 mg, from the product label.

Nature's Way

See all Nature's Way products
Name
Nature's Way Brands, LLC
City
Green Bay
State
WI
ZipCode
54311
Phone Number
1-800-962-8873
Web Address
naturesway.com
Pharmacist Counseling Corner

St. John's Wort 300 mg by Nature's Way: Common Questions

Does St. John's Wort 300 mg by Nature's Way interact with any medications?
Yes. Based on its ingredients, St. John's Wort 300 mg has a known interaction with 1,347 medications, including 755 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
St. John's Wort 300 mg contains 3 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Does this product contain St. John's Wort?
Yes — the main active ingredient is St. John's Wort flower, leaf, and stem extract. However, it's also blended with spirulina and rosemary, so this isn't a pure St. John's Wort supplement.
Can I take this if I'm pregnant or breastfeeding?
The safety data on file is limited. For rosemary, medicinal doses should be avoided in pregnancy due to insufficient data — food amounts are likely fine, but this is a concentrated extract. There's no pregnancy or breastfeeding data on file for spirulina or the St. John's Wort blend. Talk with your doctor or pharmacist before using this during pregnancy or while breastfeeding.
What side effects might I experience?
Spirulina commonly causes abdominal cramps, bloating, diarrhea, dizziness, fatigue, flatulence, headache, nausea, or vomiting in people who take it orally. Allergic reactions including rashes or itching can occur, and in rare cases, severe allergic reactions like anaphylaxis. A small number of people reported mild gum bleeding or bruising.
Is spirulina safe quality-wise?
Quality varies across products, and some spirulina supplements have been contaminated with toxins or heavy metals. Check the brand's testing standards and source before buying.
Will rosemary help with memory?
Rosemary is possibly effective for memory support based on the evidence we hold. That said, it's one of three active ingredients in this blend, so the overall effect depends on all three working together.
Can this cause seizures?
Undiluted rosemary oil or its camphor content might trigger seizures in some people. This product is a capsule extract, not undiluted oil, but it's worth mentioning to your doctor or pharmacist if you have a seizure history.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

St. John's Wort 300 mg label
Sources

Sources & How We Checked

St. John's Wort 300 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 194 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

Blue-green Algae 22 references
  1. Jensen GS, Ginsberg DJ, Huerta P, et al. Consumption of Aphanizomenon flos-aquae has rapid effects on the circulation and function of immune cells in humans. A novel approach to nutritional mobilization of the immune system. JANA 2000;2:50-6.
  2. Iwasa M, Yamamoto M, Tanaka Y, et al. Spirulina-associated hepatotoxicity. Am J Gastroenterol 2002;97:3212-13. PubMed
  3. Hayashi O, Katoh T, Okuwaki Y. Enhancement of antibody production in mice by dietary Spirulina platensis. J Nutr Sci Vitaminol (Tokyo) 1994;40:431-41.. PubMed
  4. Vitale S, Miller NR, Mejico LJ, et al. A randomized, placebo-controlled, crossover clinical trial of super blue-green algae in patients with essential blepharospasm or Meige syndrome. Am J Ophthalmol 2004;138:18-32. PubMed
  5. Mani UV, Desai S, Iyer U. Studies on the long-term effect of spirulina supplementation on serum lipid profile and glycated proteins in NIDDM patients. J Nutraceut 2000;2(3):25-32. DOI
  6. Chiu HF, Yang SP, Kuo YL, et al. Mechanisms involved in the antiplatelet effect of C-phycocyanin. Br J Nutr 2006;95:435-40. PubMed
  7. Hsiao G, Chou PH, Shen MY, et al. C-phycocyanin, a very potent and novel platelet aggregation inhibitor from Spirulina platensis. J Agric Food Chem 2005;53:7734-40.
  8. Katz M, Levine AA, Kol-Degani H, Kav-Venaki L. A compound herbal preparation (CHP) in the treatment of children with ADHD: a randomized controlled trial. J Atten Disord 2010;14:281-91. PubMed
  9. Madhyastha, H. K., Radha, K. S., Sugiki, M., Omura, S., and Maruyama, M. Purification of c-phycocyanin from Spirulina fusiformis and its effect on the induction of urokinase-type plasminogen activator from calf pulmonary endothelial cells. Phytomedicine PubMed
  10. Mazokopakis, E. E., Karefilakis, C. M., Tsartsalis, A. N., Milkas, A. N., and Ganotakis, E. S. Acute rhabdomyolysis caused by Spirulina (Arthrospira platensis). Phytomedicine. 2008;15(6-7):525-527. PubMed
  11. Halidou, Doudou M., Degbey, H., Daouda, H., Leveque, A., Donnen, P., Hennart, P., and Dramaix-Wilmet, M. [The effect of spiruline during nutritional rehabilitation: systematic review]. Rev.Epidemiol.Sante Publique 2008;56(6):425-431.
  12. Konno, T., Umeda, Y., Umeda, M., Kawachi, I., Oyake, M., and Fujita, N. [A case of inflammatory myopathy with widely skin rash following use of supplements containing Spirulina]. Rinsho Shinkeigaku 2011;51(5):330-333. PubMed
  13. Le TM, Knulst AC, Röckmann H. Anaphylaxis to Spirulina confirmed by skin prick test with ingredients of Spirulina tablets. Food Chem Toxicol 2014;74:309-10. PubMed
  14. Rzymski P, Niedzielski P, Kaczmarek N, Jurczak T, Klimaszyk P. The multidisciplinary approach to safety and toxicity assessment of microalgae-based food supplements following clinical cases of poisoning. Harmful Algae 2015;46:34-42. DOI
  15. Petrus M, Culerrier R, Campistron M, et al. First case report of anaphylaxis to spirulin: identification of phycocyanin as responsible allergen. Allergy 2010;65(7):924-5. PubMed
  16. Marles RJ, Barrett ML, Barnes J, et al. United States Pharmacopeia safety evaluation of spirulina. Crit Rev Food Sci Nutr 2011;51(7):593-604. PubMed
  17. Majdoub H, Ben Mansour M, Chaubet F, et al. Anticoagulant activity of a sulfated polysaccharide from the green alga Arthrospira platensis. Biochim Biophys Acta 2009;1790(10):1377-81. PubMed
  18. Cha BG, Kwak HW, Park AR, et al. Structural characteristics and biological performance of silk fibroin nanofiber containing microalgae spirulina extract. Biopolymers 2014;101(4):307-18. PubMed
  19. Jensen GS, Drapeau C, Lenninger M, Benson KF. Clinical safety of a high dose of phycocyanin-enriched aqueous extract from Arthrospira (Spirulina) platensis: results from a randomized, double-Blind, placebo-controlled study with a focus on anticoagulant ac
  20. Hamedifard Z, Milajerdi A, Reiner Z, Taghizadeh M, Kolahdooz F, Asemi Z. The effects of spirulina on glycemic control and serum lipoproteins in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis of randomized con
  21. Moradi S, Zobeiri M, Feizi A, Clark CCT, Entezari MH. The effects of spirulina (Arthrospira platensis) supplementation on anthropometric indices, blood pressure, sleep quality, mental health, fatigue status and quality of life in patients with ulcerative
  22. Ghanbari F, Amerizadeh A, Behshood P, Moradi S, Asgary S. Effect of microalgae arthrospira on biomarkers of glycemic control and glucose metabolism: a systematic Review and meta-analysis. Curr Probl Cardiol 2022;47(10):100942. PubMed

See these in context on the Blue-green Algae monograph →

Rosemary 20 references
  1. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  2. Foster S, Tyler VE. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed., Binghamton, NY: Haworth Herbal Press, 1993.
  3. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  4. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  5. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  6. Cartier LC, Lehrer A, Malo JL. Occupational asthma caused by aromatic herbs. Allergy 1996;51:647-9. DOI
  7. Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol 1999;246:667-70. PubMed
  8. Swain AR, Dutton SP, Truswell AS. Salicylates in foods. J Am Diet.Assoc 1985;85(8):950-60. DOI
  9. Zhu BT, Loder DP, Cai MX, et al. Dietary administration of an extract from rosemary leaves enhances the liver microsomal metabolism of endogenous estrogens and decreases their uterotropic action in CD-1 mice. Carcinogenesis 1998;19(10):1821-7. PubMed
  10. Debersac P, Heydel JM, Amiot MJ, et al. Induction of cytochrome P450 and/or detoxication enzymes by various extracts of rosemary: description of specific patterns. Food Chem Toxicol 2001;39(9):907-18. PubMed
  11. Debersac P, Vernevaut MF, Amiot MJ, et al. Effects of a water-soluble extract of rosemary and its purified component rosmarinic acid on xenobiotic-metabolizing enzymes in rat liver. Food Chem Toxicol 2001;39(2):109-17. PubMed
  12. Lee JJ, Jin YR, Lee JH, et al. Antiplatelet activity of carnosic acid, a phenolic diterpene from Rosmarinus officinalis. Planta Med 2007;73(2):121-7.
  13. Yamamoto J, Yamada K, Naemura A, et al. Testing various herbs for antithrombotic effect. Nutrition 2005;21(5):580-7. PubMed
  14. Naemura A, Ura M, Yamashita T, et al. Long-term intake of rosemary and common thyme herbs inhibits experimental thrombosis without prolongation of bleeding time. Thromb Res 2008;122(4):517-22. PubMed
  15. Lee JJ, Jin YR, Lim Y, et al. Antiplatelet activity of carnosol is mediated by the inhibition of TXA2 receptor and cytosolic calcium mobilization. Vascul Pharmacol 2006;45:148-53. PubMed
  16. Bakirel, T., Bakirel, U., Keles, O. U., Ulgen, S. G., and Yardibi, H. In vivo assessment of antidiabetic and antioxidant activities of rosemary (Rosmarinus officinalis) in alloxan-diabetic rabbits. J Ethnopharmacol 2-28-2008;116(1):64-73. PubMed
  17. Erenmemisoglu, A., Saraymen, R., and Ustun, S. Effect of a Rosmarinus officinalis leave extract on plasma glucose levels in normoglycaemic and diabetic mice. Pharmazie 1997;52(8):645-646.
  18. Valones MAA, Silva ICG, Gueiros LAM, Leão JC, Caldas AF Jr, Carvalho AAT. Clinical assessment of rosemary-based toothpaste (Rosmarinus officinalis Linn.): A randomized controlled double-blind study. Braz Dent J. 2019;30(2):146-151. PubMed
  19. Quirarte-Báez SM, Zamora-Perez AL, Reyes-Estrada CA, et al. A shortened treatment with rosemary tea (rosmarinus officinalis) instead of glucose in patients with diabetes mellitus type 2 (TSD). J Popul Ther Clin Pharmacol. 2019;26(4):e18-e28.
  20. Al Jamal A. Effect of rosemary (Rosmarinus officinalis) on lipid profiles and blood glucose in human diabetic patients (type-2). African J. Biochem. Res. 2014;8(8):147-50. DOI

See these in context on the Rosemary monograph →

St. John's Wort 152 references
  1. Miller LG. Herbal Medicinals: Selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med 1998;158:2200-11.
  2. Gulick RM, McAuliffe V, Holden-Wiltse J, et al. Phase I studies of hypericin, the active compound in St. John's Wort, as an antiretroviral agent in HIV-infected adults. AIDS Clinical Trials Group Protocols 150 and 258. Ann Intern Med 1999;130:510-4. PubMed
  3. O'Breasail AM, Argouarch S. Hypomania and St John's wort. Can J Psychiatry 1998;43:746-7.
  4. Johne A, Brockmoller J, Bauer S, et al. Pharmacokinetic interaction of digoxin with an herbal extract from St John's wort (Hypericum perforatum). Clin Pharmacol Ther 1999;66:338-45.
  5. Gordon JB. SSRIs and St. John's Wort: possible toxicity? Am Fam Physician 1998;57:950, 953.
  6. Golsch S, Vocks E, Rakoski J, et al. [Reversible increase in photosensitivity to UV-B caused by St. John's wort extract]. Hautarzt 1997;48:249-52.
  7. Bove GM. Acute neuropathy after exposure to sun in a patient treated with St. John's Wort. Lancet 1998;352:1121-2. PubMed
  8. Brockmoller J, Reum T, Bauer S, et al. Hypericin and pseudohypericin: pharmacokinetics and effects on photosensitivity in humans. Pharmacopsychiatry 1997;30:94-101. PubMed
  9. Upton R, ed. St. John's wort, Hypericum perforatum: Quality control, analytical and therapeutic monograph. Santa Cruz, CA: American Herbal Pharmacopoeia 1997;1-32.
  10. Muller WE, Singer A, Wonnemann M, et al. Hyperforin represents the neurotransmitter reuptake inhibiting constituent of hypericum extract. Pharmacopsychiatry 1998;31:16-21.
  11. Abul-Ezz SR, Barone GW, Gurley BJ, et al. Effect of herbal supplements on cyclosporine blood levels and associated acute rejection. Am Soc of Nephrol Ann Mtg, Toronto, CAN 2000;Oct. 11-16:abstract A3754.
  12. Piscitelli SC, Burstein AH, Chaitt D, et al. Indinavir concentrations and St John's wort. Lancet 2000;355:547-8. PubMed
  13. Yue QY, Bergquist C, Gerden B. Safety of St. John's wort (Hypericum perforatum). Lancet 2000;355:576-7. PubMed
  14. Ruschitzka F, Meier PJ, Turina M, et al. Acute heart transplant rejection due to Saint John's wort. Lancet 2000;355:548-9. PubMed
  15. Roberts JE, Wang RH, Tan IP, et al. Hypericin (active ingredient in St. John's wort) photo-oxidation of lens proteins. Photochem Photobiol 1999;69:42S.
  16. Gurley BJ, Barone GW. Herb-drug interaction involving St. John's wort and cyclosporine. AAPS Ann Mtg & Expo Indianapolis, IN:2000;Oct 29- Nov 2: presentation #3443.
  17. Durr D, Stieger B, Kullak-Ublick GA, et al. St. John's Wort induces intestinal P-glycoprotein/MDR1 and intestinal and hepatic CYP3A4. Clin Pharmacol Ther 2000;68:598-604. PubMed
  18. Lee A, Minhas R, Ito S, et al. Safety of St. John's wort during breastfeeding. Clin Pharmacol Ther 2000;67:130, abstract PII-64.
  19. Schneck C. St. John's wort and hypomania. J Clin Psychiatry 1998;59:689. PubMed
  20. Nierenberg AA, Burt T, Matthews J, et al. Mania associated with St. John's wort. Biol Psychiatry 1999;46:1707-8. PubMed
  21. Nebel A, Schneider BJ, Baker RA, et al. Potential metabolic interaction between St. John's wort and theophylline. Ann Pharmacother 1999;33:502. PubMed
  22. Moses EL, Mallinger AG. St. John's wort: Three cases of possible mania induction. J Clin Psychopharmacol 2000;20:115-7. PubMed
  23. Beckman SE, Sommi RW, Switzer J. Consumer use of St. John's wort: A survey of effectiveness, safety, and tolerability. Pharmacotherapy 2000;20:568-74.
  24. Peirce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York, NY: William Morrow and Co., 1999.
  25. Mai I, Kruger H, Budde K, et al. Hazardous pharmacokinetic interaction of Saint John's wort (Hypericum perforatum) with the immunosuppressant cyclosporin. Int J Clin Pharmacol Ther 2000;38:500-2. PubMed
  26. Schempp CM, Muller K, Winghofer B, et al. Single-dose and steady-state administration of Hypericum perfotatum extract (St. John's wort) does not influence skin sensitivity to UV radiation, visible light, and solar-stimulated radiation. Arch Dermatol 2001;
  27. Schempp CM, Ludtke R, Winghofer B, Simon JC. Effect of topical application of hypericum perforatum extract on skin sensitivity to solar simulated radiation. Photodermatol Photoimmunol Photomed 2000;16:125-8.
  28. Jacobson JM, Feinman L, Liebes L, et al. Pharmacokinetics, safety, and antiviral effects of hypericin, a derivative of St. John's Wort plant, in patients with chronic hepatitis C virus infection. Antimicrob Agents Chemother 2001;45:517-24. PubMed
  29. Moschella C, Jaber BL. Interaction between cyclosporine and Hypericum perforatum (St. John's wort) after organ transplantation. Amer J Kidney Dis 2001;38:1105-7. PubMed
  30. Karliova M, Treichel U, Malago M, et al. Interaction of Hypericum perforatum (SJW) with cyclosporin A metabolism in a patient after liver transplantation. J Hepatol 2000;33:853-5.
  31. Mandelbaum A, Pertzborn F, Martin-Facklam M, Wiesel M. Unexplained decrease of cyclosporin trough levels in a compliant renal transplant patient. Nephrol Dial Transplant 2000;15:1473-4. PubMed
  32. Assalian P. Sildenafil for SJW-induced sexual dysfunction. J Sex Marital Ther 2000;26:357-8.
  33. de Maat M, Hoetelmans R, Mathot R, et al. Drug interaction between St. John's wort and nevirapine. AIDS 2001;15:420-1. PubMed
  34. Schrader E. Equivalence of St. John's wort extract (Ze 117) and fluoxetine: a randomized, controlled study in mild-moderate depression. Int Clin Psychopharmacol 2000;15:61-8.
  35. Ernst E, Rand JI, Barnes J, Stevinson C. Adverse effects profile of the herbal antidepressant St. John's wort (Hypericum perforatum L.). Eur J Clin Pharmacol 1998;54:589-94. PubMed
  36. Shelton RC, Keller MB, Gelenberg A, et al. Effectiveness of St. John's wort in major depression: A randomized, placebo-controlled trial. JAMA 2001;285:1978-86. DOI
  37. Breidenbach T, Hoffmann MW, Becker T, et al. Drug interaction of St. John's wort with cyclosporin. Lancet 2000;355:1912.
  38. Brown TM. Acute St. John's wort toxicity. Am J Emerg Med 2000;18:231-2. PubMed
  39. Kleber E, Obry T, Hippeli S, et al. Biochemical activities of extracts from Hypericum perforatum L. 1st Communication: inhibition of dopamine-beta-hydroxylase. Arzneimittelforschung 1999;49:106-9.
  40. Barone GW, Gurley BJ, Ketel BL, et al. Drug interaction between St. John's wort and cyclosporin. Ann Pharmacother 2000;34:1013-6.
  41. Cheng TO. St. John's wort interaction with digoxin [letter]. Arch Intern Med 2000;160:2548. PubMed
  42. Lane-Brown MM. Photosensitivity associated with herbal preparations of St. John's wort (Hypericum perforatum). Med J Aust 2000;172:302.
  43. Mathijssen RHJ, Verweij J, De Bruijn P, et al. Modulation of irinotecan (CPT-11) metabolism by St. John's wort in cancer patients. American Association for Cancer Research Annual Meeting, San Francisco, April 2002. Abstract 2443.
  44. Mai I, Bauer S, Krueger H, et al. Wechselwirkungen von Johaniskraut mit tacrolismus bei nierentransplantierten patienten. Symposium Phytopharmaka VII. Forschung und Klinische Anwendung, Berlin, October, 2001.
  45. Bhopal JS. St John's wort-induced sexual dysfunction. Can J Psychiatry 2001;46:456-457. PubMed
  46. Schulz V. Incidence and clinical relevance of the interactions and side effects of Hypericum preparations. Phytomedicine 2001;8:152-60.
  47. Gorski JC, Hamman MA, Wang Z, et al. The effect of St. John's wort on the efficacy of oral contraceptives (abstract MPI-80). Clin Pharmacol Ther 2001;71:P25.
  48. Hennessy M, Kelleher D, Spiers JP, et al. St Johns wort increases expression of P-glycoprotein: implications for drug interactions. Br J Clin Pharmacol 2002;53:75-82.
  49. Parker V, Wong AH, Boon HS, Seeman MV. Adverse reactions to St John's Wort. Can J Psychiatry 2001;46:77-9. PubMed
  50. Patel S, Robinson R, Burk M. Hypertensive crisis associated with St. John's Wort. Am J Med 2002;112:507-8. PubMed
  51. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  52. Holme SA, Roberts DL. Erythroderma associated with St John's wort. Br J Dermatol 2000;143:1127-8. PubMed
  53. Irefin S, Sprung J. A possible cause of cardiovascular collapse during anesthesia: long-term use of St. John's Wort. J Clin Anesth 2000;12:498-9. PubMed
  54. Calapai G, Crupi A, Firenzuoli F, et al. Serotonin, norepinephrine and dopamine involvement in the antidepressant action of hypericum perforatum. Pharmacopsychiatry 2001;34:45-9. PubMed
  55. Henderson L, Yue QY, Bergquist C, et al. St John's wort (Hypericum perforatum): drug interactions and clinical outcomes. Br J Clin Pharmacol 2002;54:349-56..
  56. Mathijssen RH, Verweij J, de Bruijn P, et al. Effects of St. John's wort on irinotecan metabolism. J Natl Cancer Inst 2002;94:1247-9.. PubMed
  57. Ladner DP, Klein SD, Steiner RA, Walt H. Synergistic toxicity of delta-aminolaevulinic acid-induced protoporphyrin IX used for photodiagnosis and hypericum extract, a herbal antidepressant. Br J Dermatol 2001;144:916-8. PubMed
  58. Ernst E. St. John's Wort supplements endanger the success of organ transplantation. Arch Surg 2002;137:316-9. PubMed
  59. Wang Z, Hamman MA, Huang SM, et al. Effect of St. John's wort on the pharmacokinetics of fexofenadine. Clin Pharmacol Ther 2002;71:414-20.. PubMed
  60. Chan LY, Chiu PY, Lau TK. A study of hypericin-induced teratogenicity during organogenesis using a whole rat embryo culture model. Fertil Steril 2001;76:1073-4. PubMed
  61. Schwarz UI, Buschel B, Kirch W. Unwanted pregnancy on self-medication with St John's wort despite hormonal contraception. Br J Clin Pharmacol 2003;55:112-3. PubMed
  62. Logan JL, Ahmed J. Critical hypokalemic renal tubular acidosis due to Sjogren's syndrome: association with the purported immune stimulant echinacea. Clin Rheumatol 2003;22:158-9.
  63. Mai I, Stormer E, Bauer S, et al. Impact of St John's wort treatment on the pharmacokinetics of tacrolimus and mycophenolic acid in renal transplant patients. Nephrol Dial Transplant 2003;18:819-22.. PubMed
  64. Groning R, Breitkreutz J, Muller RS. Physico-chemical interactions between extracts of Hypericum perforatum L. and drugs. Eur J Pharm Biopharm 2003;56:231-6.. PubMed
  65. Sugimoto K, Ohmori M, Tsuruoka S, et al. Different effects of St John's wort on the pharmacokinetics of simvastatin and pravastatin. Clin Pharmacol Ther 2001;70:518-24.. DOI
  66. Bauer S, Stormer E, Johne A, et al. Alterations in cyclosporin A pharmacokinetics and metabolism during treatment with St John's wort in renal transplant patients. Br J Clin Pharmacol 2003;55:203-11.. PubMed
  67. Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St. John's wort on drug metabolism by induction of cytochrome P450 3A4 enzyme. JAMA 2003;290:1500-4.. PubMed
  68. Hypericum Depression Trial Study Group. Effect of Hypericum perforatum (St. John's wort) in major depressive disorder: a randomized controlled trial. JAMA 2002;287:1807-14. PubMed
  69. Hammerness P, Basch E, Ulbricht C, et al. St. John's wort: a systematic review of adverse effects and drug interactions for the consultation psychiatrist. Psychosomatics 2003;44:271-82. PubMed
  70. Gurley BJ, Gardner SF, Hubbard MA, et al. Cytochrome P450 phenotypic ratios for predicting herb-drug interactions in humans. Clin Pharmacol Ther 2002;72:276-87.. PubMed
  71. Foster BC, Vandenhoek S, Hana J, et al. In vitro inhibition of human cytochrome P450-mediated metabolism of marker substrates by natural products. Phytomedicine 2003;10:334-42.. PubMed
  72. Kim RB. Drugs as P-glycoprotein substrates, inhibitors, and inducers. Drug Metab Rev 2002;34:47-54. PubMed
  73. Dean AJ, Moses GM, Vernon JM. Suspected withdrawal syndrome after cessation of St. John's wort. Ann Pharmacother 2003;37:150. PubMed
  74. Morimoto T, Kotegawa T, Tsutsumi K, et al. Effect of St. John's wort on the pharmacokinetics of theophylline in healthy volunteers. J Clin Pharmacol 2004;44:95-101. PubMed
  75. Pfrunder A, Schiesser M, Gerber S, et al. Interaction of St John's wort with low-dose oral contraceptive therapy: a randomized controlled trial. Br J Clin Pharmacol 2003;56:683-90. PubMed
  76. Hall SD, Wang Z, Huang SM, et al. The interaction between St John's wort and an oral contraceptive. Clin Pharmacol Ther 2003;74:525-35. PubMed
  77. Frye RF, Fitzgerald SM, Lagattuta TT, et al. Effect of St. John's wort on imatinib mesylate pharmacokinetics. Clin Pharmacol Ther 2004;76:323-9. PubMed
  78. Komoroski BJ, Zhang S, Cai H, et al. Induction and inhibition of cytochromes P450 by the St. John's wort constituent hyperforin in human hepatocyte cultures. Drug Metab Dispos 2004;32:512-8. PubMed
  79. Jiang X, Williams KM, Liauw WS, et al. Effect of St John's wort and ginseng on the pharmacokinetics and pharmacodynamics of warfarin in healthy subjects. Br J Clin Pharmacol 2004;57:592-9. PubMed
  80. Shimizu K, Nakamura M, Isse K, Nathan PJ. First-episode psychosis after taking an extract of Hypericum perforatum (St John's Wort). Hum Psychopharmacol 2004;19:275-6.
  81. Szegedi A, Kohnen R, Dienel A, Kieser M. Acute treatment of moderate to severe depression with hypericum extract WS 5570 (St John's wort): randomised controlled double blind non-inferiority trial versus paroxetine. BMJ 2005;330:503. PubMed
  82. Lau WC, Carville DGM, Guyer KE, et al. St. John's Wort Enhances the Platelet Inhibitory Effect of Clopidogrel in Clopidogrel "Resistant" Healthy Volunteers. American College of Cardiology Annual Meeting, Orlando, FL 2005: Presentation 1043-129.
  83. Murphy PA, Kern SE, Stanczyk FZ, Westhoff CL. Interaction of St. John's Wort with oral contraceptives: effects on the pharmacokinetics of norethindrone and ethinyl estradiol, ovarian activity and breakthrough bleeding. Contraception 2005;71:402-8. PubMed
  84. Linde K, Knuppel L. Large-scale observational studies of hypericum extracts in patients with depressive disorders - a systematic review. Phytomedicine 2005;12:148-57. PubMed
  85. Dasgupta A, Hovanetz M, Olsen M, et al. Drug-herb interaction: effect of St John's wort on bioavailability and metabolism of procainamide in mice. Arch Pathol Lab Med 2007;131:1094-8. PubMed
  86. Dugoua JJ, Mills E, Perri D, Koren G. Safety and efficacy of St. John's wort (hypericum) during pregnancy and lactation. Can J Clin Pharmacol 2006;13:e268-76.
  87. Jiang X, Blair EY, McLachlan AJ. Investigation of the effects of herbal medicines on warfarin response in healthy subjects: a population pharmacokinetic-pharmacodynamic modeling approach. J Clin Pharmacol 2006;46:1370-8. PubMed
  88. Niederhofer H. St. John's wort may diminish methylphenidate's efficacy in treating patients suffering from attention deficit hyperactivity disorder. Med Hypotheses 2007;68:1189. PubMed
  89. Bell EC, Ravis WR, Lloyd KB, Stokes TJ. Effects of St. John's wort supplementation on ibuprofen pharmacokinetics. Ann Pharmacother 2007;41:229-34. PubMed
  90. Booth JN, McGwin G. The association between self-reported cataracts and St. John's Wort. Curr Eye Res 2009;34:863-6. PubMed
  91. Samadi S, Khadivzadeh T, Emami A, et al. The effect of Hypericum perforatum on the wound healing and scar of cesarean. J Altern Complement Med 2010;16:113-7.
  92. Wang LS, Zhu B, Abd El-Aty A, et al. The influence of St. John's wort on CYP2C19 activity with respect to genotype. J Clin Pharmacol 2004;44:577-81. PubMed
  93. Weber W, Vander Stoep A, McCarty RL, et al. Hypericum perforatum (St John's wort) for attention-deficit/hyperactivity disorder in children and adolescents: a randomized controlled trial. JAMA 2008;299:2633-41. PubMed
  94. Lee, A., Minhas, R., Matsuda, N., Lam, M., and Ito, S. The safety of St. John's wort (Hypericum perforatum) during breastfeeding. J Clin Psychiatry 2003;64(8):966-968.
  95. Eich-Hochli, D., Oppliger, R., Golay, K. P., Baumann, P., and Eap, C. B. Methadone maintenance treatment and St. John's Wort - a case report. Pharmacopsychiatry 2003;36(1):35-37. PubMed
  96. Smith M, Lin KM, and Zheng YP. PIII-89 an open trial of nifedipine-herb interactions: Nifedipine with St. John's wort, ginseng or ginkgo biloba. Clin Pharm Ther 2001;69:P86.
  97. Kawaguchi, A., Ohmori, M., Tsuruoka, S., Nishiki, K., Harada, K., Miyamori, I., Yano, R., Nakamura, T., Masada, M., and Fujimura, A. Drug interaction between St John's Wort and quazepam. Br.J.Clin Pharmacol. 2004;58(4):403-410. PubMed
  98. Dresser, G. K., Schwarz, U. I., Wilkinson, G. R., and Kim, R. B. Coordinate induction of both cytochrome P4503A and MDR1 by St John's wort in healthy subjects. Clin Pharmacol Ther 2003;73(1):41-50. PubMed
  99. Patel, J., Buddha, B., Dey, S., Pal, D., and Mitra, A. K. In vitro interaction of the HIV protease inhibitor ritonavir with herbal constituents: changes in P-gp and CYP3A4 activity. Am.J.Ther. 2004;11(4):262-277. PubMed
  100. Xu, H., Williams, K. M., Liauw, W. S., Murray, M., Day, R. O., and McLachlan, A. J. Effects of St John's wort and CYP2C9 genotype on the pharmacokinetics and pharmacodynamics of gliclazide. Br.J.Pharmacol. 2008;153(7):1579-1586.
  101. Wang, L. S., Zhou, G., Zhu, B., Wu, J., Wang, J. G., Abd El-Aty, A. M., Li, T., Liu, J., Yang, T. L., Wang, D., Zhong, X. Y., and Zhou, H. H. St John's wort induces both cytochrome P450 3A4-catalyzed sulfoxidation and 2C19-dependent hydroxylation of omepr
  102. Hojo, Y., Echizenya, M., Ohkubo, T., and Shimizu, T. Drug interaction between St John's wort and zolpidem in healthy subjects. J.Clin.Pharm.Ther. 2011;36(6):711-715. PubMed
  103. Izzo, A. A. and Ernst, E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs 2009;69(13):1777-1798. PubMed
  104. Barbenel, D. M., Yusufi, B., O'Shea, D., and Bench, C. J. Mania in a patient receiving testosterone replacement postorchidectomy taking St John's wort and sertraline. J Psychopharmacol 2000;14(1):84-86.
  105. Ratz, A. E., von Moos, M., and Drewe, J. [St. John's wort: a pharmaceutical with potentially dangerous interactions]. Schweiz Rundsch.Med Prax. 5-10-2001;90(19):843-849.
  106. Guzelcan, Y., Scholte, W. F., Assies, J., and Becker, H. E. [Mania during the use of a combination preparation with St. John's wort (Hypericum perforatum)]. Ned.Tijdschr.Geneeskd. 10-6-2001;145(40):1943-1945.
  107. van Gurp, G., Meterissian, G. B., Haiek, L. N., McCusker, J., and Bellavance, F. St John's wort or sertraline? Randomized controlled trial in primary care. Can Fam Physician 2002;48:905-912.
  108. Lecrubier, Y., Clerc, G., Didi, R., and Kieser, M. Efficacy of St. John's wort extract WS 5570 in major depression: a double-blind, placebo-controlled trial. Am J Psychiatry 2002;159(8):1361-1366. PubMed
  109. Schempp, C. M., Winghofer, B., Muller, K., Schulte-Monting, J., Mannel, M., Schopf, E., and Simon, J. C. Effect of oral administration of Hypericum perforatum extract (St. John's Wort) on skin erythema and pigmentation induced by UVB, UVA, visible light
  110. Zullino, D. and Borgeat, F. Hypertension induced by St. John's Wort - a case report. Pharmacopsychiatry 2003;36(1):32. PubMed
  111. Nanayakkara, P. W., Meijboom, M., and Schouten, J. A. [Suicidal and aggressive thoughts as a result of taking a Hypericum preparation (St. John's wort)]. Ned.Tijdschr.Geneeskd. 6-11-2005;149(24):1347-1349.
  112. Fava, M., Alpert, J., Nierenberg, A. A., Mischoulon, D., Otto, M. W., Zajecka, J., Murck, H., and Rosenbaum, J. F. A Double-blind, randomized trial of St John's wort, fluoxetine, and placebo in major depressive disorder. J.Clin.Psychopharmacol. 2005;25(5 PubMed
  113. Gastpar, M., Singer, A., and Zeller, K. Comparative efficacy and safety of a once-daily dosage of hypericum extract STW3-VI and citalopram in patients with moderate depression: a double-blind, randomised, multicentre, placebo-controlled study. Pharmacops PubMed
  114. Cappuzzo, K. A. Herbal product use in a patient with polypharmacy. Consult Pharm. 2006;21(11):911-915. PubMed
  115. Papakostas, G. I., Crawford, C. M., Scalia, M. J., and Fava, M. Timing of clinical improvement and symptom resolution in the treatment of major depressive disorder. A replication of findings with the use of a double-blind, placebo-controlled trial of Hyp DOI
  116. Sardella, A., Lodi, G., Demarosi, F., Tarozzi, M., Canegallo, L., and Carrassi, A. Hypericum perforatum extract in burning mouth syndrome: a randomized placebo-controlled study. J.Oral Pathol.Med. 2008;37(7):395-401.
  117. Etogo-Asse, F., Boemer, F., Sempoux, C., and Geubel, A. Acute hepatitis with prolonged cholestasis and disappearance of interlobular bile ducts following tibolone and Hypericum perforatum (St. John's wort). Case of drug interaction? Acta Gastroenterol.Be
  118. Andreescu, C., Mulsant, B. H., and Emanuel, J. E. Complementary and alternative medicine in the treatment of bipolar disorder--a review of the evidence. J.Affect.Disord. 2008;110(1-2):16-26. PubMed
  119. Kasper, S., Volz, H. P., Moller, H. J., Dienel, A., and Kieser, M. Continuation and long-term maintenance treatment with Hypericum extract WS 5570 after recovery from an acute episode of moderate depression--a double-blind, randomized, placebo controlled
  120. Al-Akoum, M., Maunsell, E., Verreault, R., Provencher, L., Otis, H., and Dodin, S. Effects of Hypericum perforatum (St. John's wort) on hot flashes and quality of life in perimenopausal women: a randomized pilot trial. Menopause. 2009;16(2):307-314. PubMed
  121. Brattstrom, A. Long-term effects of St. John's wort (Hypericum perforatum) treatment: a 1-year safety study in mild to moderate depression. Phytomedicine. 2009;16(4):277-283. PubMed
  122. Canning, S., Waterman, M., Orsi, N., Ayres, J., Simpson, N., and Dye, L. The efficacy of Hypericum perforatum (St John's wort) for the treatment of premenstrual syndrome: a randomized, double-blind, placebo-controlled trial. CNS.Drugs 2010;24(3):207-225. PubMed
  123. Van Strater, A. C. and Bogers, J. P. Interaction of St John's wort (Hypericum perforatum) with clozapine. Int.Clin.Psychopharmacol. 2012;27(2):121-124. PubMed
  124. Sultana D, Peindl KS Wisner KL. Rash associated with St. John's wort treatment in premenstrual dysphoric disorder. Arch Women Ment Health 2000;3:99-101. DOI
  125. Bernd A, Ramirez-Bosca A, Kippenberger S, and et al. Phototoxic effects of Hypericum extract in cultures of human keratinocytes compared with those of psoralen. Photochem Photobiol 1999;2(69):218-221.
  126. Woelk H, Burkard G, and Grunwald J. Nutzen und Risikobewertung des Hypericum-extraktes LI 160 auf der Basis einer Drug-Monitoring-Studie mit 3250 patienten. Nervenheilkunde 1993;12:308-313.
  127. Schakau D, Hiller K, Schultz-Zehden W, and et al. Risk/benefit profile of St.John's wort extract: STEI 300 in 2404 patients with various degrees of psychiatric disturbance. Psychopharmakotherapie 1996;3:116-122.
  128. Laird RD and Webb M. Psychotic episode during use of St John's wort. J Herbal Pharmacother 2001;1(2):81-87. DOI
  129. Schrader E, Meier B, and Brattstrom A. Hypericum treatment of mild-moderate depression in a placebo-controlled study. A prospective, double-blind, randomized, placebo-controlled, multicentre study. Human Psychopharm 1998;13:163-169. DOI
  130. Dolton MJ, Mikus G, Weiss J, et al. Understanding variability with voriconazole using a population pharmacokinetic approach: implications for optimal dosing. J Antimicrob Chemother 2014;69(6):1633-41. PubMed
  131. Goey AK, Meijerman I, Rosing H, et al. The effect of St John's wort on the pharmacokinetics of docetaxel. Clin Pharmacokinet 2014;53(1):103-10. PubMed
  132. Lei HP, Yu XY, Xie HT, et al. Effect of St. John's wort supplementation on the pharmacokinetics of bupropion in healthy male Chinese volunteers. Xenobiotica 2010;40(4):275-81. PubMed
  133. Gurok MG, Mermi O, Kilic F, et al. Psychotic episode induced by St. John's wort (Hypericum perforatum): a case report. J Mood Dis 2014;4(1):38-40. DOI
  134. Yildirim O, Canan F. A case of panic attack induced by St John's wort. Prim Care Companion CNS Disord 2013;15(1). pii: PCC.12l01453. PubMed
  135. Abdali K, Khajehei M, Tabatabaee HR. Effect of St John's wort on severity, frequency, and duration of hot flashes in premenopausal, perimenopausal and postmenopausal women: a randomized, double-blind, placebo-controlled study. Menopause 2010;17(2):326-31. PubMed
  136. Trana C, Toth G, Wijns W, Barbato E. St. John's Wort in patients non-responders to clopidogrel undergoing percutaneous coronary intervention: a single-center randomized open-label trial (St. John's Trial). J Cardiovasc Transl Res 2013;6(3):411-4. PubMed
  137. Agollo MC, Miszputen SJ, Diament J. Hypericum perforatum-induced hepatotoxicity with possible association with copaiba (copaifera langsdorffii desf): a case report. Einstein (Sao Paulo) 2014;12(3):355-7.
  138. Hohmann N, Maus A, CarlsA, Haefeli WE, Mikus G. St. John's wort treatment in women bears risks beyond pharmacokinetic drug interactions. Arch Toxico. 2016;90(4):1013-15. doi:10.1007/s00204-015-1532-7. PubMed
  139. Jackson A, D'Avolio A, Moyle G, et al. Pharmacokinetics of the co-administration of boceprevir and St. John's wort to male and female healthy volunteers. J Antimicrob Chemother 2014;69:1911-1915. PubMed
  140. Jones D. Tourian LT, Margolese H. Possible association of syndrome of Inappropriate secretion of antidiuretic hormone with St. John's wort use. J of Clin Psychopharmacol 2014:34(6):759-60. PubMed
  141. Soleymani S, Bahramsoltani R, Rahimi R, Abdollahi M. Clinical risks of St John's Wort (Hypericum perforatum) co-administration. Expert Opin Drug Metab Toxicol. 2017;13(10):1047-62.
  142. Chrubasik-Hausmann S, Vlachojannis J, McLachlan AJ. Understanding drug interactions with St John's wort (Hypericum perforatum L.): impact of hyperforin content. J Pharm Pharmacol. 2018.
  143. Market C, Kastner IM, Hellwig, et al. The effect of induction of CYP3A4 by St. John's wort on ambrisentan plasma kinetics in volunteers of known CY2C19 genotype. Basic & Clinical Pharmacology & Toxicology 2015;116:423-428.
  144. Loughren MJ, Kharasch ED, Kelton-Rehkopf MC, Syrjala KL, Shen DD. Influence of St. John's wort on intravenous fentanyl pharmacokinetics, pharmacodynamics, and clinical effects: a randomized clinical trial. Anesthesiology 2020;132(3):491-503. PubMed
  145. Scholz I, Liakoni E, Hammann F, et al. Effects of Hypericum perforatum (St. John's wort) on the pharmacokinetics and pharmacodynamics of rivaroxaban in humans. Br J Clin Pharmacol. 2020. doi: 10.1111/bcp.14553.
  146. Fisher KA, Patel P, Abualula S, Concepion L. St. John's Wort-Induced Supraventricular Tachycardia. Cureus. 2021 Apr 7;13(4):e14356. PubMed
  147. Schäfer W, Wentzell N, Schink T, Haug U. Characterization of pregnancies exposed to St. John's wort and their outcomes: A claims data analysis. Reprod Toxicol. 2021 Jun;102:90-97. PubMed
  148. Adibelli Z, Karacay I, Demir M, Duran C. St. John's Wort (Hypericum perforatum)-related acute kidney injury. Blood Purif. 2021 Aug 24:1-3. doi: 10.1159/000518349.
  149. Sarris J, Ravindran A, Yatham LN, et al. Clinician guidelines for the treatment of psychiatric disorders with nutraceuticals and phytoceuticals: The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety T
  150. Haron MH, Dale O, Martin K, et al. Evaluation of the Herb-Drug Interaction Potential of Commonly Used Botanicals on the US Market with Regard to PXR- and AhR-Mediated Influences on CYP3A4 and CYP1A2. J Diet Suppl 2022. PubMed
  151. Pochet S, Lechon AS, Lescrainier C, et al. Herb-anticancer drug interactions in real life based on VigiBase, the WHO global database. Sci Rep 2022;12(1):14178. PubMed
  152. Gümüs KS, Teegelbekkers A, Sauter M, et al. Effect of Tacrolimus Formulation (Prolonged-Release vs Immediate-Release) on Its Susceptibility to Drug-Drug Interactions with St. John's Wort. Clin Pharmacol Drug Dev 2024. PubMed

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DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

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