Terpenes are a family of compounds that are widely distributed in the plant world. Some have biological activity while others are used only for various commercial purposes. These are substances that occur in most of the essential oils and resins in plants. For instance terpenes are the major components in the oils of citrus fruits and they include the bioflavanoids and the carotenoids.
These substances combat fungal bacterial infections and there are many stories claiming that terpenes are helpful in the treatment of glaucoma, spastic symptoms of multiple sclerosis, spinal lesions and in reducing the severity of side effects of chemotherapy.