What is it used for?
(Traditionally) used in Herbal Medicine (as an expectorant) to help relieve mucus buildup of the (upper) respiratory tract/catarrhs [Source note 2].
For multi-ingredient products:
To prevent the product from being represented as a "traditional medicine", any indicated traditional use claim must refer to the specific active ingredient(s) and recognized traditional system of medicine from which the claim originates when 1) both traditional and modern claims are present or 2) when claims originate from multiple systems of traditional medicine (e.g., Thuja is traditionally used in Herbal Medicine as an expectorant to help relieve mucus buildup of the respiratory tract).
When ALL of the active ingredients (MIs) in the product are used within the SAME identified system of traditional medicine AND the product makes ONLY traditional claims, listing of MIs in the traditional claim(s) is not required.
Who does this guide cover?
Adults 18 years and older
How is it taken?
Oral
Which forms are covered?
this reference excludes foods or food-like dosage forms as indicated in the Compendium of references Guidance Document.
Quantities
Methods of preparation: Dry, Powdered, Non-Standardized Extracts (Dry Extract*, Tincture, Fluid extract, Decoction, Decoction concentrate, Infusion, Infusion concentrate)
1 – 2 grams dried herb tops, 3 times per day [Source note 3].
*Note: Solvents allowed for the method of preparation “Non-Standardized Extracts (Dry extract)” as part of this reference are ethanol and/or water only.
How is it used?
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
How long is it used?
For occasional use only [Source note 4].
Warnings and precautions
Ask a healthcare professional if symptoms persist or worsen.
Ask a healthcare professional before use if you are breastfeeding [Source note 5].
Ask a healthcare professional before use if you are taking other herbs containing thujone (e.g., wormwood, sage, tansy, and juniper) [Source note 6].
When should it be avoided?
Do not use if you are pregnant [Source note 7].
Possible side effects
The reference does not require an additional label statement in this section. This does not establish an absence of risk.
Storage
Must be established in accordance with the requirements described in the applicable product regulations.
Preparation details
Ingredient identity, preparation requirements, and other details that define the scope of this guide.
Ingredients and preparations
| Proper name(s) | Common name(s) | Source information / Source material(s) | Source information / Part(s) | Source information / Preparation(s) |
|---|---|---|---|---|
| Thuja occidentalis |
| Thuja occidentalis | Herb top | Dry |
References: Proper name: USDA 2025; Common names: Gardner and McGuffin 2013; Source information: BHP 1983; Felter and Lloyd 1983.
Other ingredients
Must be chosen from the current supplements Ingredient Database (source ingredient database) and must meet the limitations outlined in the database.
Preparation and quality requirements
The finished product specifications must be established in accordance with the requirements described in the source authority source’s product quality guidance.
The active ingredient must comply with the requirements outlined in the source ingredient database.
Guide change history
Updates to this SupplementSafety.org guide.
Minor updates
Updated guide wording, organization, and source presentation. Added our editorial change history.
Initial release
Initial SupplementSafety.org guide prepared from source reference material.
Validation: Not yet completed. Editorial updates do not constitute clinical validation.
Sources
Source information
This guide organizes source material about uses, preparations, amounts, and precautions. Read the conditions alongside each statement; the information may apply only to particular preparations or populations.
The source document includes supporting references. We have not independently summarized or assessed every cited study for this guide.
- Source document version
- June 26, 2026
- Source captured
- Aug 15, 2026
- Editorial work
- Editorial preparation. Independent clinical review has not been recorded for this guide.
Full citations are available through the link above. Verification is required to open them; reading this guide does not require verification.
Taking a medication too?
Explore our supplement–medication interaction checker. Its coverage and review status are shown with the results; a missing finding does not establish that a combination is safe.