Thuja Occidentalis: Uses, Side Effects & Dosage Guide

Thuja occidentalis is a tree. The leaves of this plant are used as a drug for various purposes. Another name of the Thuja occidentalis is northern white cedar and eastern white cedar. Thuja occidentalis is also known as arborvitae.

Most of the people used the Thuja occidentalis as an ornament plant. Most of the people use Thuja occidentalis for the treatment of respiratory disorders such as rhinosinusitis (inflammation of nasal mucosa), bronchitis (infection of the lungs), Tonsillitis (inflammation of tonsils), and herpes labialis also called as cold sores. Some studies also show that Thuja occidentalis may help treat osteoarthritis and other abnormal bone conditions. But there is no specific data available to prove these pieces of evidence.

Thuja is also used as a flavouring agent in some foods.

Ancient people were used the leaves of the Thuja occidentalis for the treatment of various abnormalities including:

  • bronchial catarrh
  • Enuresis
  • Cystitis
  • Psoriasis
  • uterine carcinomas
  • Amenorrhea
  • rheumatism 

Nowadays Thuja occidentalis is widely used in homoeopathy as tincture or dilution. Thuja occidentalis can also be used in combination with other medicinal plants to enhance their action. These plants which can be used along with the Thuja occidentalis are:

  • Echinacea purpurea
  • Echinacea pallida
  • Baptisia tinctoria

This combination is advantageous in the treatment for severe acute or chronic bacterial infections, including sinusitis, bronchitis, pharyngitis, and otitis media.

HIV-1 Activity

Some studies showed that thuja occidentalis might be helpful in patients with HIV. The polysaccharides of Thuja occidentalis can prevent cell death caused by human immunodeficiency virus (HIV). Some studies have shown that the HIV-1 activity of Thuja occidentalis is dose-dependent.

Spleen Cell Proliferation

Thuja occidentalis can impart beneficial effects on the spleen, and it can cause the cells of the spleen.

CD4-positive T Cells

Recent studies show that the polysaccharides of Thuja occidentalis can proliferate and differentiate the T cells, especially T helper cells. The count of CD4 positive T cells significantly increased.


Thuja occidentalis is indicated in the following conditions, but there is a need for more studies to evaluate its effectiveness.

  • Bronchitis
  • Pneumonia
  • Common cold
  • Stimulating immune function
  • Skin infections
  • Nerve pain
  • Osteoarthritis
  • Joint pain
  • Strep throat
  • Abortions
  • Muscle aches
  • Skin diseases
  • Use as an insect repellent
  • Other conditions
  • Cancer
  • Warts


Thuja occidentalis is strongly contraindicated in patients having:

  • Pregnancy
  • Breastfeeding
  • Patients with kidney and liver failure
  • If drug interactions present
  • Cardiac patients
  • Patients with epilepsy
  • Peptic ulcers
  • Gastric and intestinal inflammation

Side Effects

Some studies have shown that thuja occidentalis can activate the immune system, so taking the Thuja occidentalis by the patient having an autoimmune disorder like systemic lupus erythematosus, multiple sclerosis, and rheumatoid arthritis. The signs and symptoms of these conditions may become severe by taking thuja occidentalis. Thuja occidentalis can also cause seizures in some patients.

Thuja occidentalis have following side effects:

  • Queasiness
  • Vomiting
  • Diarrhoea
  • Miscarriage  
  • Seizures
  • Low blood pressure
  • Allergic reactions
  • Headache
  • Drowsiness
  • Sleepiness  
  • Death


Thuja occidentalis has various drug interactions, and their care should be taken if anyone taking the drugs given below:

  • General anaesthesia like propofol
  • antiarrhythmics (mexiletine)
  • Amphotericin
  • Penicillin
  • Cephalosporins
  • Imipenem 
  • antidepressants (bupropion)
  • antihistamines (cyproheptadine)
  • immunosuppressants (cyclosporine)
  • narcotics (fentanyl)
  • stimulants (methylphenidate)
  • Theophylline

These medications can increase the chance of seizures if taking with Thuja occidentalis there the use of thuja occidentalis should be avoided in this case or consult with your doctor.

Thuja occidentalis interacts with anti seizures drugs also. Thuja occidentalis may decrease the effectiveness of the anti seizures drugs their thuja occidentalis should be avoided with anti seizures drugs also. Some drugs which have interactions with the Thuja occidentalis are as follow:

  • Phenobarbital
  • primidone (Mysoline)
  • valproic acid (Depakene)
  • gabapentin (Neurontin)
  • carbamazepine (Tegretol)
  • phenytoin (Dilantin)

Thuja occidentalis leaves contain an oil called thujone. This oil may cause kidney and liver damage and can also lead to convulsions and seizures. If Thuja occidentalis is taken orally in large quantities, it can lead to hallucinations and muscle spasm, which sometimes prove fatal. If you are taking Thuja occidentalis orally along with other herbs containing thujone oil, then consult with your doctor or stop taking thuja occidentalis. The other herbs containing the thujone oil are as follow:

  • juniper
  • mugwort
  • oakmoss
  • Oriental arborvitae
  • sage
  • tansy
  • tree moss
  • wormwood

Consult with your doctor before applying Thuja occidentalis on your skin if you have low blood circulation problem or diabetes mellitus.

High-Risk Groups

  • Pregnant mothers
  • Lactating mothers
  • Patients with a history of epilepsy and any other type of seizures
  • Cardiac patients
  • Patients with kidney and liver failure