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Dietary supplement

Thuja Ingredients & Drug Interactions

by Herbs Etc.

Thuja label
See full label image
Liquid Category: Botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Thuja 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: Moderate

Thuja is a dietary supplement by Herbs Etc. with 1 active ingredient. Its ingredients are commonly taken for warts and skin growths, respiratory and immune support, cold and upper respiratory symptoms.Based on those ingredients, 576 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are fresh Thuja. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Thuja by Herbs Etc.

Ask about any prescription or over-the-counter medication and we check it for interactions with Thuja by Herbs Etc. — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Thuja by Herbs Etc.

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 11, 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 1 active ingredient.

This product contains one active ingredient: fresh thuja, a plant used traditionally in herbal medicine. The liquid form also contains 40% grain alcohol and purified water as inactive ingredients.

Does it work?

Couldn't assess
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 assessable

This is a single-ingredient Thuja product and its label doesn't state a use — see Thuja's own graded uses on its monograph.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

The evidence we hold does not establish that thuja is effective for treating the common cold. The data shows insufficient reliable evidence to rate it for that use.

The evidence, ingredient by ingredient Thuja

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 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

Thuja carries real safety concerns, especially in larger doses. The plant contains thujone, a neurotoxin that in high amounts has been linked to headache, restlessness, seizures, stomach upset, vomiting, abdominal pain, diarrhea, and in severe cases liver damage, kidney damage, and death.

Skin contact with thuja plants can also cause a contact rash on the hands in some people. Thuja should not be used in pregnancy — the safety data rates it likely unsafe because it has traditionally been used to stimulate the uterus and bring on menstruation.

It's also rated likely unsafe while breastfeeding, and there isn't enough data to know whether it's safe to pass to a nursing infant.

Side effects, ingredient by ingredient Thuja

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?
  • 1 of the 1 matched ingredient can interact with medications — Thuja.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: seizure medications; immunosuppressants / transplant drugs.
  • For scale: 576 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 with your pharmacist before using this product if you take seizure threshold lowering drugs (such as certain anesthetics), anticonvulsants, or immunosuppressants. These are all rated Moderate severity interactions, and thuja may increase seizure risk or reduce how well your medications work.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFormula with limited ingredient disclosure with no assessable stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Thuja is not established to work for colds and carries significant safety red flags, especially around seizures and immune suppression. If you take seizure threshold lowering drugs, anticonvulsants, or immunosuppressants, you should avoid this product.

Do not use it if you're pregnant or breastfeeding. Talk to your pharmacist before starting.

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

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Sep 25, 2015.

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 Thuja, straight from the product label.

Brand Herbs Etc.
Net contents 8 fl. Oz.; 236 mL
Market status On market
Date entered into DSLD Sep 25, 2015
DSLD ID 50678
Product type Botanical
Supplement form Liquid
Dietary claims / uses No Claim
Intended target group(s) Adult (18 - 50 Years)
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 Thuja by Herbs Etc., 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:
0 Not Present
Maximum serving Sizes:
0 Not Present
IngredientAmount% DV
fresh Thuja0 NP--

Other ingredients: 40% Grain Alcohol, purified Water

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

Professional strength

Fresh leaf extract

For dispensing purposes only

Herbal Single

FDA Statement of Identity

Fast-Acting Dietary Supplement

General

99209

Formula

Thuja occidentalis

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Thuja by Herbs Etc. label

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

Thuja 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 Thuja by Herbs Etc.

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size0 Not Present Dosage formLiquid Amounts shown are per serving.

Fresh Thuja

Interacts with
576 drugs
0 NP per serving

Thuja, also called northern white cedar or arborvitae, is a tree whose leaf and oil have a long history in folk and homeopathic medicine, especially f...

Fresh Thuja monograph & interactions

Other (inactive) ingredients: 40% Grain Alcohol, Purified Water. These complete the product’s ingredient list but are not active constituents.

Interaction report

Thuja by Herbs Etc. Drug Interactions

Want to check YOUR meds against Thuja?

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
576Drugs
576 Moderate

Ingredients driving the most interactions

fresh Thuja 576

Individual Drug Interactions

The ingredients in Thuja interact with 576 drugs. Click any drug to see the details.

1 of the 1 ingredient in Thuja interact with drugs. Each result below shows which ingredient is responsible. fresh Thuja

Each ingredient & the kinds of drugs it affects

For each ingredient in Thuja with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

fresh Thuja3 drug types · 576 drugs

Anticonvulsants

Thuja products can contain thujone, which might lower the seizure threshold. Theoretically, this could decrease the effectiveness of anticonvulsants drugs.

Likelihood Possible Evidence D
Immunosuppressants

Thuja might stimulate immune function. Theoretically, taking thuja might decrease the effects of immunosuppressive therapy. Immunosuppressant drugs include azathioprine (Imuran), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), muromonab-CD3 (OKT3, Orthoclone OKT3), mycophenolate (CellCept), tacrolimus (FK506, Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone), and other corticosteroids (glucocorticoids).

Likelihood Possible Evidence D
Seizure Threshold Lowering Drugs

Thuja products can contains significant amounts of thujone, a neurotoxin. Theoretically, patients taking drugs that lower the seizure threshold might be at greater risk of seizure if they also take thuja. Advise patients taking these drugs to avoid thuja products. Some drugs that lower the seizure threshold include anesthetics (propofol, others), antiarrhythmics (mexiletine), antibiotics (amphotericin, penicillin, cephalosporins, imipenem), antidepressants (bupropion, others), antihistamines (cyproheptadine, others), immunosuppressants (cyclosporine), narcotics (fentanyl, others), stimulants (methylphenidate), theophylline, and others.

Likelihood Possible Evidence D
fresh Thuja full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Thuja, from the product label.

Herbs Etc.

Name
Herbs, Etc.
Street Address
1340 Rufina Circle
City
Santa Fe
State
NM
ZipCode
87507
Web Address
www.herbsetc.com
Pharmacist Counseling Corner

Thuja by Herbs Etc.: Common Questions

Does Thuja by Herbs Etc. interact with any medications?
Yes. Based on its ingredients, Thuja has a known interaction with 576 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Thuja contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism 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.
Can I take thuja if I'm pregnant?
No — thuja is rated likely unsafe in pregnancy. It has traditionally been used to stimulate the uterus and bring on menstruation, so it should be avoided. If you're pregnant or planning to become pregnant, talk to your doctor or pharmacist before using any thuja product.
Is thuja safe while breastfeeding?
No — the safety data rates thuja likely unsafe while breastfeeding. There isn't enough information to know whether it's safe to pass to a nursing infant, so it's best to avoid it during that time.
What are the side effects of thuja?
Large doses have been reported to cause headache, nervousness, seizures, stomach irritation, vomiting, abdominal pain, and diarrhea. In severe cases, thuja toxicity has caused liver damage, kidney damage, and death. Skin contact with thuja plants can also cause an itchy rash on the hands.
Does thuja work for colds?
The evidence we hold does not establish that thuja is effective for the common cold. There's insufficient reliable evidence to rate it for that use.
Why does thuja interact with seizure drugs?
Thuja contains thujone, a compound that can be toxic to the nervous system and may lower your seizure threshold. If you're already taking a drug meant to prevent or manage seizures, thuja could potentially work against it or increase your seizure risk.

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.

Thuja label
Go deeper

The Full Monographs Behind Thuja’s Ingredients

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

Herb & supplement monograph

Thuja

Interacts with 576 drugs

Thuja, also called northern white cedar or arborvitae, is a tree whose leaf and oil have a long history in folk and homeopathic medicine, especially for warts and immune support. Solid human...

Read the full Thuja monograph →
Sources

Sources & How We Checked

Thuja'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 10 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.

Thuja 10 references
  1. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
  2. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  3. Millet Y, Jouglard J, Steinmetz MD, et al. Toxicity of some essential plant oils. Clinical and experimental study. Clin Toxicol 1981;18:1485-98. PubMed
  4. Gohla SH, Haubeck HD, Neth RD. Mitogenic activity of high molecular polysaccharide fractions isolated from the Cupressaceae Thuja occidentale L. I. Macrophage-dependent induction of CD-4-positive T-helper (Th+) lymphocytes. Leukemia 1988;2:528-33.
  5. Fetrow CW, Avila JR. Professional's Handbook of Complementary & Alternative Medicines. 1st ed. Springhouse, PA: Springhouse Corp., 1999.
  6. Henneicke-von Zepelin H, Hentschel C, Schnitker J, et al. Efficacy and safety of a fixed combination phytomedicine in the treatment of the common cold (acute viral respiratory tract infection): results of a randomised, double blind, placebo-controlled, m
  7. Naser, B., Bodinet, C., Tegtmeier, M., and Lindequist, U. Thuja occidentalis (Arbor vitae): A Review of its Pharmaceutical, Pharmacological and Clinical Properties. Evid.Based Complement Alternat.Med 2005;2(1):69-78.
  8. Patel R, Alavi F, Ortega S, Matela A. Herb-Induced Liver Injury by Cimicifuga racemosa and Thuja occidentalis Herbal Medications for Fertility. Case Rep Gastrointest Med 2021;2021:8858310. PubMed
  9. Ambooken B, Thomas M, Jisha KT. Papillary Eccrine Adenoma in a 5-year-old Girl Altered by Application of Thuja Ointment. J Cutan Aesthet Surg 2020;13(4):370-371. PubMed
  10. Badaoui A, Fougerousse AC. Contact dermatitis to linalool and limonene: Unusual sources of exposure. Ann Dermatol Venereol 2023;150(2):167-168. PubMed

See these in context on the Thuja monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

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.

© 2021 Therapeutic Research Center, LLC

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