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

David Winston's Herb-Cal Ingredients & Drug Interactions

by Herbalist & Alchemist

David Winston's Herb-Cal label
See full label image
Liquid Category: Botanical
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking David Winston's Herb-Cal against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Major

David Winston's Herb-Cal is a dietary supplement by Herbalist & Alchemist with 5 active ingredients. Its ingredients are commonly taken for lowering cholesterol, heart and digestive health, soothing itchy or irritated skin.Based on those ingredients, 1,304 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are Chamomile flowers extract, Alfalfa herb extract, Horsetail herb extract. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against David Winston's Herb-Cal by Herbalist & Alchemist

Ask about any prescription or over-the-counter medication and we check it for interactions with David Winston's Herb-Cal by Herbalist & Alchemist — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of David Winston's Herb-Cal by Herbalist & Alchemist

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

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Jul 12, 2026

What’s inside

Low disclosure
Ingredient Transparency · database check
Low

Most active ingredients don't disclose an individual amount — you can't tell how much of each you're getting.

Why this rating?
  • The label discloses an exact amount for 0 of its 5 active ingredients.
  • “Proprietary Blend” is a proprietary blend — the label gives one combined amount (2 mL) without saying how much of each component you get.

This liquid contains five active herbal extracts: oat milky seed, stinging nettle leaf, chamomile flowers, horsetail herb, and alfalfa herb. The product also contains three inactive ingredients — vinegar extract, distilled water, and ethyl alcohol — which serve as preservative and vehicle for delivery.

Each herb brings its own traditional and researched properties to the blend, though their combined effects in this specific formula are not independently studied.

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: Maintains healthy bone structure.
  • We looked for evidence on: Osteoporosis, Osteoarthritis, Bone density, Skeletal health, Fracture prevention.
  • The closest evidence on file: Stinging Nettle is rated "Insufficient Reliable Evidence To Rate" for Osteoarthritis (Natural Medicines).
  • Also on file: Oats is rated "Insufficient Reliable Evidence To Rate" for Osteoarthritis.
  • Also on file: Horsetail is rated "Insufficient Reliable Evidence To Rate" for Osteoporosis.

The evidence for this product's overall effectiveness is not established in our data. Looking at the individual ingredients: oat extract is likely effective for high cholesterol (dyslipidemia) and heart disease, and stinging nettle is possibly effective for blood-sugar control in diabetes — but for most of stinging nettle's other traditional uses (hay fever, anemia, asthma, enlarged prostate, gum health), the evidence is insufficient to rate.

Chamomile, horsetail, and alfalfa have insufficient evidence for their commonly claimed uses. The blend as a whole hasn't been formally evaluated.

The evidence, ingredient by ingredient Oats Stinging Nettle German Chamomile Horsetail Alfalfa

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 5 of the 5 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 5 of 5.
  • General safety write-ups exist for 5 of 5.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Oats are generally well tolerated and considered likely safe in pregnancy and while breastfeeding, though concentrated supplements are less studied than whole food. The most common side effects are digestive — bloating, gas, and abdominal distension — which usually ease with continued use.

Stinging nettle should be avoided in pregnancy due to traditional concerns about effects on the uterus, and it's unsafe while breastfeeding. Chamomile is best avoided in pregnancy unless your doctor approves, and has limited safety data for breastfeeding.

Horsetail should be avoided in both pregnancy and breastfeeding. Alfalfa has estrogen-like activity and is best avoided at supplement doses during pregnancy, and caution is advised for breastfeeding.

All ingredients can cause allergic reactions in sensitive people — chamomile may trigger reactions in those sensitive to ragweed. Rare serious effects (like a lupus-like syndrome with alfalfa or liver injury with stinging nettle) have been reported but are uncommon.

Side effects, ingredient by ingredient Oats Stinging Nettle German Chamomile Horsetail Alfalfa

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 5 of the 5 matched ingredients can interact with medications — Alfalfa, Stinging Nettle, Oats, Horsetail, German Chamomile.
  • The most serious interaction on file is rated Major.
  • Some involve high-stakes drug classes: anticoagulant / antiplatelet drugs; immunosuppressants / transplant drugs; diabetes medications; lithium.
  • For scale: 1,305 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.

Before taking this product, check with your pharmacist if you take warfarin or other blood thinners (alfalfa and stinging nettle contain vitamin K), diabetes medications or insulin (oats, stinging nettle, horsetail, and alfalfa may lower blood sugar), lithium (stinging nettle and horsetail may raise its level), diuretics (stinging nettle and horsetail may worsen potassium loss), HIV medications like efavirenz or other NRTIs (horsetail may reduce their effectiveness), birth control pills or estrogen therapy (chamomile and alfalfa may interfere), sedatives or CNS depressants (chamomile may add to drowsiness), or drugs broken down by your liver's CYP2D6, CYP2C9, or CYP3A4 enzymes (chamomile may raise their levels).

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with no established evidence rating for its marketed use. Major medication interactions have been identified, and safety information is well characterized.

If you take blood thinners, diabetes medications, lithium, diuretics, HIV drugs, birth control, or sedatives, check this product with your pharmacist or doctor first — multiple ingredients here can interact. If you're pregnant or breastfeeding, talk with your doctor before using it.

For people with no medication conflicts and not pregnant, the digestive herbs here are generally tolerated, though you may notice bloating or gas at first.

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

Assessment coverage: 5 of 5 active ingredients matched to our full ingredient reviews (monographs). Based on the product label dated Nov 21, 2019.

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 David Winston's Herb-Cal, straight from the product label.

Brand Herbalist & Alchemist
Barcode (UPC) 667056115937
Net contents 2 fl. Oz.; 60 mL
Market status On market
Date entered into DSLD Nov 21, 2019
DSLD ID 209102
Product type Botanical
Supplement form Liquid
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Kosher
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 David Winston's Herb-Cal by Herbalist & Alchemist, 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:
1.5 mL
Maximum serving Sizes:
2 mL
Servings per container
30
UPC/BARCODE
667056115937
IngredientAmount% DV
Proprietary Blend2 mL--
Oat milky seed extract0 NP--
Stinging Nettle leaf extract0 NP--
Chamomile flowers extract0 NP--
Horsetail herb extract0 NP--
Alfalfa herb extract0 NP--

Other ingredients: Vinegar extract, distilled Water, Ethyl Alcohol

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.
General Statements

Maintains healthy bone structure

FDA Statement of Identity

Herbal Supplement

Suggested/Recommended/Usage/Directions

Suggested use: 30-40 drops (1.5-2 mL) in juice or water. Take 3 times per day. Shake well before using.

Precautions

Keep out of children's reach

FDA Disclaimer Statement

This statement has not been evaluated by the FDA. This product is not intended todiagnose, treat, cure or prevent any disease.

Seals/Symbols

OK

Formula

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See for yourself

David Winston's Herb-Cal by Herbalist & Alchemist label

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

David Winston's Herb-Cal label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in David Winston's Herb-Cal by Herbalist & Alchemist

These are the 5 active ingredients this product is made of. Select any to open its full monograph.

Serving size1.5 mL Dosage formLiquid Servings per container30 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.

Other (inactive) ingredients: Vinegar extract, Distilled Water, Ethyl Alcohol. These complete the product’s ingredient list but are not active constituents.

Interaction report

David Winston's Herb-Cal by Herbalist & Alchemist Drug Interactions

Want to check YOUR meds against David Winston's Herb-Cal?

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
1,304Drugs
2 Major 1,274 Moderate 28 Minor

Ingredients driving the most interactions

Chamomile flowers extract 960
Alfalfa herb extract 583
Horsetail herb extract 188
Stinging Nettle leaf extract 164
Oat milky seed extract 86

Individual Drug Interactions

The ingredients in David Winston's Herb-Cal interact with 1,304 drugs. Click any drug to see the details.

5 of the 5 ingredients in David Winston's Herb-Cal interact with drugs. Each result below shows which ingredient is responsible. Chamomile flowers extract Alfalfa herb extract Horsetail herb extract Stinging Nettle leaf extract Oat milky seed extract

Each ingredient & the kinds of drugs it affects

For each ingredient in David Winston's Herb-Cal 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.

Chamomile flowers extract9 drug types · 960 drugs

Cns Depressants

Theoretically, German chamomile might have additive effects when used with CNS depressants.
German chamomile has mild sedative effects. Theoretically, concomitant use with drugs with sedative properties can cause additive effects and side effects.

Likelihood Possible Evidence D
Contraceptive Drugs

Theoretically, large amounts of German chamomile might reduce the effectiveness of oral contraceptives.
In vitro, German chamomile has demonstrated antiestrogenic activity. Theoretically, concomitant use of large amounts of German chamomile might interfere with contraceptive drugs through competition for estrogen receptors.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, German chamomile might inhibit CYP2C9 and increase levels of drugs metabolized by these enzymes.
In vitro evidence shows that German chamomile might inhibit CYP2C9. So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP2C9 in patients taking German chamomile.

Likelihood Possible Evidence D
Cytochrome P450 2D6 (Cyp2D6) Substrates

Theoretically, German chamomile might inhibit CYP2D6 and increase levels of drugs metabolized by these enzymes.
In vitro evidence shows that German chamomile might inhibit CYP2D6. So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP2D6 in patients taking German chamomile.

Likelihood Possible Evidence D
Cytochrome P450 3A4 (Cyp3A4) Substrates

Theoretically, German chamomile might inhibit CYP3A4 and increase levels of drugs metabolized by these enzymes.
In vitro evidence shows that German chamomile might inhibit CYP3A4. So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP3A4 in patients taking German chamomile.

Likelihood Possible Evidence D
Estrogens

Theoretically, large amounts of German chamomile might reduce the effectiveness of estrogens.
In vitro, German chamomile has demonstrated antiestrogenic activity. Theoretically, large amounts of German chamomile might interfere with hormone replacement therapy through competition for estrogen receptors.

Likelihood Possible Evidence D
Tamoxifen (Nolvadex)

Theoretically, large amounts of German chamomile might interfere with the activity of tamoxifen.
In vitro, German chamomile has demonstrated antiestrogenic activity.

Likelihood Possible Evidence D
Warfarin (Coumadin)

German chamomile might increase the effects of warfarin and increase the risk of bleeding.
In one case, a 70-year-old female taking warfarin developed retroperitoneal hematoma and bilateral recti muscle bleeding along with an INR of 7.9 following ingestion of German chamomile tea 4-5 cups daily and use of a topical chamomile-based lotion applied 4-5 times daily.

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

Theoretically, German chamomile might inhibit CYP1A2 and increase levels of drugs metabolized by these enzymes.
In vitro and animal research shows that German chamomile might inhibit CYP1A2. So far, this interaction has not been reported in humans. However, there might be an increase in the levels of drugs metabolized by CYP1A2 in patients taking German chamomile.

Likelihood Possible Evidence D
Chamomile flowers extract full monograph & interactions

Alfalfa herb extract6 drug types · 583 drugs

Warfarin (Coumadin)

Theoretically, alfalfa might reduce the anticoagulant activity of warfarin.
Alfalfa contains a large amount of vitamin K. This could theoretically interfere with the activity of warfarin.

Likelihood Probable Evidence D
Antidiabetes Drugs

Theoretically, alfalfa might increase the risk of hypoglycemia when taken with antidiabetes drugs.
Animal research suggests that alfalfa decreases blood sugar in diabetic mice. Also, in one case report, a diabetic patient experienced hypoglycemia after consuming alfalfa extract. Monitor blood glucose levels closely. Dose adjustments might be necessary.

Likelihood Possible Evidence D
Contraceptive Drugs

Theoretically, alfalfa might interfere with the activity of contraceptive drugs.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.

Likelihood Possible Evidence D
Estrogens

Theoretically, alfalfa might interfere with hormone therapy.
Alfalfa contains coumestrol, a phytoestrogen, and isoflavonoids, which have estrogenic effects.

Likelihood Possible Evidence D
Immunosuppressants

Theoretically, alfalfa might decrease the efficacy of immunosuppressive therapy.
In vitro research and human case reports suggest that alfalfa may have immunostimulant effects.

Likelihood Possible Evidence D
Photosensitizing Drugs

Theoretically, concomitant use of alfalfa with photosensitizing drugs might have additive effects.
Animal research suggests that excessive doses of alfalfa may increase photosensitivity, possibly due to its chlorophyll content. It is unclear if this effect would be clinically relevant in humans.

Likelihood Possible Evidence D
Alfalfa herb extract full monograph & interactions

Horsetail herb extract5 drug types · 188 drugs

Antidiabetes Drugs

Theoretically, taking horsetail with antidiabetes drugs might increase the risk of hypoglycemia.
Equisetum myriochaetum has demonstrated hypoglycemic activity in clinical research. In an animal diabetic model, Equisetum giganteum had hypoglycemic effects. It is unclear whether other horsetail species have hypoglycemic effects.

Likelihood Possible Evidence D
Diuretic Drugs

Theoretically, taking horsetail with diuretic drugs might increase potassium loss and the risk of hypokalemia.
Laboratory research shows that various species of horsetail have diuretic properties. Due to its diuretic effects, there has been concern that taking horsetail along with potassium-depleting diuretics might increase the risk for hypokalemia. However, pharmacokinetic research in humans shows that taking horsetail 900 mg daily for 4 days does not affect urinary excretion of electrolytes, including potassium and sodium, despite having a diuretic effect similar to taking hydrochlorothiazide 25 mg daily. It is unclear if taking horsetail for a longer duration would affect electrolyte levels. Until more is known, use with caution.

Likelihood Possible Evidence D
Efavirenz (Sustiva)

Theoretically, horsetail might decrease the levels and clinical effects of efavirenz.
In two case reports, patients were found to have detectable viral loads when taking horsetail-containing supplements along with an antiretroviral regimen that included efavirenz. In one case, the antiretroviral regimen included zidovudine, lamivudine, and efavirenz; in the other case, the regimen consisted of emtricitabine, tenofovir disoproxil fumarate, and efavirenz. One month after discontinuing horsetail, the viral loads became undetectable in both cases. The exact mechanism of this interaction is unknown. It is also unclear if this interaction is specific to efavirenz or if it is related to various components of antiretroviral therapy.

Likelihood Possible Evidence D
Lithium

Theoretically, horsetail might increase the levels and adverse effects of lithium.
Animal research suggests that horsetail has diuretic properties. Theoretically, due to these potential diuretic effects, horsetail might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

Likelihood Possible Evidence D
Nucleoside Reverse Transcriptase Inhibitors (Nrtis)

Theoretically, horsetail might decrease the levels and clinical effects of NRTIs.
In two case reports, patients were found to have detectable viral loads when taking horsetail-containing supplements along with an antiretroviral therapy. In one case, the antiretroviral regimen included zidovudine, lamivudine, and efavirenz; in the other case, the regimen consisted of emtricitabine, tenofovir disoproxil fumarate, and efavirenz. One month after discontinuing the supplement, the viral loads became undetectable in both cases. The exact mechanism of these interactions is unknown. It is also unclear if these interactions are specific to NRTIs or if they are related to various components of antiretroviral therapy.

Likelihood Possible Evidence D
Horsetail herb extract full monograph & interactions

Stinging Nettle leaf extract4 drug types · 164 drugs

Antidiabetes Drugs

Theoretically, stinging nettle might have additive effects with antidiabetes drugs.
Clinical research shows that stinging nettle might decrease blood glucose levels in patients with diabetes.

Likelihood Possible Evidence B
Diuretic Drugs

Theoretically, combining stinging nettle with diuretic drugs may have additive effects.
Animal research suggests that the above ground parts and roots of stinging nettle may have a diuretic effect.

Likelihood Possible Evidence D
Lithium

Theoretically, stinging nettle might reduce excretion and increase levels of lithium.
Animal research suggests that stinging nettle has diuretic and natriuretic properties, which could alter the excretion of lithium. The dose of lithium might need to be decreased.

Likelihood Possible Evidence D
Warfarin (Coumadin)

There is some concern that stinging nettle might decrease the effects of anticoagulant drugs such as warfarin.
Stinging nettle contains a significant amount of vitamin K. When taken in large quantities, this might interfere with the activity of warfarin.

Likelihood Possible Evidence D
Stinging Nettle leaf extract full monograph & interactions

Oat milky seed extract2 drug types · 86 drugs

Antidiabetes Drugs

Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.
Consuming oats can decrease blood glucose in patients with diabetes. In those who require insulin, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.

Likelihood Possible Evidence D
Insulin

Concomitant use of oats and insulin might increase the risk of hypoglycemia.
In patients with insulin-dependent type 2 diabetes, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control.

Likelihood Possible Evidence B
Oat milky seed extract full monograph & interactions
The maker

Brand information

Manufacturer and brand details for David Winston's Herb-Cal, from the product label.

Herbalist & Alchemist

See all Herbalist & Alchemist products
Name
Herbalist & Alchemist, Inc.
City
Washington
State
NJ
ZipCode
07882
Phone Number
800-611-8235
Web Address
www.herbalist-alchemist.com
Pharmacist Counseling Corner

David Winston's Herb-Cal by Herbalist & Alchemist: Common Questions

Does David Winston's Herb-Cal by Herbalist & Alchemist interact with any medications?
Yes. Based on its ingredients, David Winston's Herb-Cal has a known interaction with 1,304 medications, including 2 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
David Winston's Herb-Cal contains 5 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.
Will this help me lower my cholesterol or protect my heart?
Oats in the blend are likely effective for high cholesterol and heart disease. The other ingredients don't have enough evidence to rate for those conditions. The blend as a whole hasn't been tested, so we can't say whether the combination works.
Is it safe to take this if I'm pregnant?
No. Stinging nettle, chamomile, horsetail, and alfalfa should all be avoided during pregnancy — there isn't enough safety data, or traditional concerns exist. Oats as food are considered safe, but this is a concentrated supplement. Talk with your doctor before taking any of it.
What are the most common side effects?
Digestive effects from the herbs — bloating, gas, abdominal distension, or loose stools — are the most frequent. These usually settle down as your body adjusts. A small number of people may have allergic reactions, especially if they're sensitive to ragweed.
Can I take this while breastfeeding?
Stinging nettle and horsetail should be avoided while breastfeeding — safety data doesn't exist. Chamomile and alfalfa are cautioned due to limited data. Talk with your doctor or pharmacist about your specific situation.
What is horsetail supposed to do in this blend?
Horsetail is traditionally used for various purposes, but the evidence is insufficient to rate its effectiveness for most of them. Because of its diuretic (fluid-removing) properties, it can interact with several medications — that's important to check before you start.
Does this product have any fillers or other ingredients?
Yes — in addition to the five active herbal extracts, it contains vinegar extract, distilled water, and ethyl alcohol as inactive ingredients that help preserve and deliver the herbs.

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.

David Winston's Herb-Cal label
Go deeper

The Full Monographs Behind David Winston's Herb-Cal’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Oats

Interacts with 86 drugs

Oats are a well-studied whole grain whose soluble fiber (beta-glucan) can help lower cholesterol and support heart health when eaten regularly. As a food, oats are safe for most people, and...

Read the full Oats monograph → Herb & supplement monograph

Stinging Nettle

Interacts with 164 drugs

Stinging nettle is a common plant used as food and in traditional medicine, most often for prostate symptoms, allergies, and joint pain. The evidence is mixed and mostly preliminary, so it i...

Read the full Stinging Nettle monograph → Herb & supplement monograph

German Chamomile

Interacts with 960 drugs

German chamomile is a widely used herbal remedy taken mainly as a tea for calming, sleep, and digestive complaints. Early research suggests possible benefits for mild anxiety and some skin o...

Read the full German Chamomile monograph → Herb & supplement monograph

Horsetail

Interacts with 188 drugs

Horsetail is a traditional herb most often used as a mild diuretic and for hair, nail, and bone support, but high-quality human evidence is limited. It can cause thiamine (vitamin B1) loss w...

Read the full Horsetail monograph → Herb & supplement monograph

Alfalfa

Interacts with 583 drugs

Alfalfa is a nutrient-rich legume that people use for high cholesterol, menopause symptoms, and general wellness, but solid human evidence for most of these uses is limited. It is best avoid...

Read the full Alfalfa monograph →
Sources

Sources & How We Checked

David Winston's Herb-Cal'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 97 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.

Oats 13 references
  1. Cooper SG, Tracey EJ. Small-bowel obstruction caused by oat-bran bezoar. N Engl J Med 1989;320:1148-9. DOI
  2. Pick ME, Hawrysh ZJ, Gee MI, et al. Oat bran concentrate bread products improve long-term control of diabetes: a pilot study. J Am Diet Assoc 1996;96:1254-61. PubMed
  3. Braaten JT, Scott FW, Wood PJ, et al. High beta-glucan oat bran and oat gum reduce postprandial blood glucose and insulin in subjects with and without type 2 diabetes. Diabet Med 1994;11:312-8.
  4. Rosario PG, Gerst PH, Prakash K, Albu E. Dentureless distention: oat bran bezoars cause obstruction. J Am Geriatr Soc 1990;38:608. PubMed
  5. Food and Drug Administration. Food labeling: health claims: oats and coronary heart disease. Fed Regist 1996;61:296-313.
  6. Foulke J. FDA Allows Whole Oat Foods To Make Health Claim on Reducing the Risk of Heart Disease. FDA Talk Paper. 1997. Available at: http://www.fda.gov/bbs/topics/ANSWERS/ANS00782.html.
  7. Chandalia M, Garg A, Lutjohann D, et al. Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. N Engl J Med 2000;342:1392-8. PubMed
  8. Lembo A, Camilleri M. Chronic constipation. N Engl J Med 2003;349:1360-8. . PubMed
  9. De Paz Arranz S, Perez Montero A, Remon LZ, Molero MI. Allergic contact urticaria to oatmeal. Allergy 2002;57:1215. . PubMed
  10. Delgado G, Kleber ME, Krämer BK, et al. Dietary intervention with oatmeal in patients with uncontrolled type 2 diabetes mellitus - A crossover study. Exp Clin Endocrinol Diabetes. 2019;127(9):623-629. PubMed
  11. Sobhan M, Hojati M, Vafaie SY, Ahmadimoghaddam D, Mohammadi Y, Mehrpooya M. The efficacy of colloidal oatmeal cream 1% as add-on therapy in the management of chronic irritant hand eczema: A double-blind study. Clin Cosmet Investig Dermatol. 2020;13:241-25
  12. Hou Q, Li Y, Li L, Cheng G, Sun X, Li S, Tian H. The metabolic effects of oats intake in patients with type 2 diabetes: A systematic review and meta-analysis. Nutrients. 2015;7(12):10369-87. PubMed
  13. González-Afonso M, Cañas JA, Sastre B, et al. A Case of Anaphylaxis After Ingestion of Oats: Research Into New Allergens. J Investig Allergol Clin Immunol 2022;32(6):506-508. PubMed

See these in context on the Oats monograph →

Stinging Nettle 23 references
  1. Monographs on the medicinal uses of plant drugs. Exeter, UK: European Scientific Co-op Phytother, 1997.
  2. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  3. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
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Horsetail 14 references
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Alfalfa 32 references
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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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