What are the health benefits of thuja?
The leaves and leaf oil from thuja – an evergreen tree that grows in Europe and North America and known botanically as Thuja occidentalis – are used in the preparation of some herbal products. The harvested leaves are dried and made into extracts, tinctures and tea that can be taken internally. Thuja is also used in creams to be applied to the skin and in homeopathic tablet and liquid form.
Herbalists have promoted thuja for many conditions, including for treating viral and bacterial infections, coughs and strep throat, for decreasing the toxic effects of radiation and chemotherapy, as a diuretic to increase urination and as a cream for treating skin ailments such as psoriasis and eczema. In herbal medicine, it may be recommended for similar health conditions along with treating depression, headaches and other problems.
Is there any evidence to support claims of health benefits from thuja?
Currently there is little or no scientific evidence to support the claimed benefits of taking thuja, and in large doses it can have serious side effects.
Thuja is listed on the MHRA traditional herbal registration as an ingredient used in a herbal product "to relieve the symptoms of the common cold, such as cough, catarrh, sore throat, runny or blocked nose, based on traditional use only". The herbal product registered also contains Echinacea and Wild indigo.
Most claims of the benefits of thuja have been based on limited laboratory experiments or individual reports. There has been no reported human clinical trial based on thuja alone.
A 2005 German study reported that 91 adults with colds and runny noses, who took a mixture of extracts that included echinacea, baptisia and thuja, used fewer facial tissues than those given a placebo. Because other extracts were used, the study cannot be used as evidence to support any benefits of using thuja alone.
Are there any risks associated with thuja?
Because there have been no human clinical studies on the use of thuja alone, there is little known about how it may interact with medicines, food or supplements. It is known that if taken in large doses internally, thuja can be toxic, and there have been reports of a number of side effects including asthma attacks, intestinal irritation and miscarriage. A component of thuja known as thujone is known to cause seizures, muscle spasms and liver and kidney damage.
Women who are pregnant or breast-feeding should not take thuja, nor should people with gastrointestinal problems, such as gastritis or ulcers, or with seizure disorders.