- Cedar leaf oil comes from the Thuja occidentalis tree. It has been used historically by different cultures to treat many conditions, including breathing disorders, cancers, headaches, heart ailments, infections, inflammatory disorders, menstrual problems, and urinary disorders. Furthermore, Thuja has been used to induce abortions.
- Thuja is closely related to other cedar genera also used as dietary supplements, including as Cedrus (common name: cedar) and Juniperus (common name: juniper).
- Very little scientific evidence exists regarding Thuja. Clinical trials evaluating Thuja alone are lacking, and the available data are questionable.
- Preclinical studies have demonstrated anticancer and immune-stimulating properties, but further research is necessary. Thuja is often used in homeopathy as a remedy for skin, urinary, and reproductive organ complaints. The herb is also used in combination with Echinacea purpurea, Echinacea pallida, and Baptisia tinctoria to relieve symptoms of common cold and upper respiratory tract infections and as supportive therapy to standard antibiotics.