evidence: Herbal remedies, also known as botanical medicine, have been used in many traditional medicine systems. They are produced from all parts of a plant including the roots, leaves, berries and flowers. These may contain active ingredients that can cause chemical changes in the body. Herbal remedies can be taken by mouth or applied to the skin to treat disease and promote health. Sometimes herbs and plants are categorised as biological treatments. [...] There is no reliable scientific evidence that herbal remedies alone can cure or treat cancer. However, some plant extracts have been found to have anti-cancer effects and have been turned into chemotherapy drugs. These include vincristine from the periwinkle plant, and taxanes from the bark of the Pacific yew tree. [...] Herbal medicines are often used to help with the side effects of conventional cancer treatments, such as lowering fatigue and improving wellbeing. Evidence shows they should be used in addition to conventional therapies, rather than as an alternative.