Although thuja appears to be safe when used in small amounts that are sometimes found in foods (it is sometimes used as a flavouring agent), it may not be safe to use as a medication or supplement, since very little is known about it.
Large doses of thuja have caused side effects such as nausea, vomiting, diarrhea, gut irritation, and bleeding from membranes lining the body (e.g., the skin lining the inside of the mouth). There have also been reports of asthma attack, liver and kidney damage, seizures, and death from taking more than the recommended amount of thuja.
Do not use thuja if you have gastrointestinal problems such as intestinal ulcers and stomach inflammation.
If the symptoms being treated with thuja persist or become worse, consult a health care provider.
Do not use thuja if you are pregnant. See your doctor first before using thuja if you are breast-feeding.
Thuja leaves contain an oil called thujone, which may cause convulsions, liver and kidney damage, muscle spasms, and hallucinations if taken orallyorallyto be taken by mouth (swallowed). If you are taking other herbs or natural products that have thujone, talk to your health care provider before using thuja. Herbs that may contain thujone include:
- oak moss
- oriental arborvitae
- tree moss
See your doctor if you have diabetes or poor blood circulation before applying thuja on the skin.
Do not take thuja if you have epilepsy or are taking anticonvulsant medications (i.e., medication that prevents seizures).
Do not take thuja if you are taking medications that may lower your seizure threshold (i.e., medications that increase your risk of having a seizure). Medications that can lower the seizure threshold include:
- antiarrhythmicantiarrhythmican agent to treat irregular heartbeats
- antibiotics (e.g., ciprofloxacin)
- antidepressants (e.g., bupropion)
- antihistamines (e.g., diphenhydramine)
- antipsychotics (e.g., clozapine)
- immunosuppressants (e.g., tacrolimus)
- narcotics (e.g., tramadol)
- stimulants (i.e., substances that have a stimulating effect, like cocaine)
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.