While evidence of its potential to treat cancer shows promise, resveratrol is not an alternative to chemotherapy. Human clinical trials are now underway to investigate whether the properties identified in laboratory and animal studies will be active against cancer in people (as a single agent or in combination with others), and determine the most effective and safe doses. Resveratrol is found in several plants and plant products, mainly in red wine and grapes. A large body of research has established that resveratrol has multiple beneficial health effects. As well as anti-inflammatory, antioxidant and cardio-protective (reducing the risk of heart disease) effects, resveratrol has also been shown to have anti-cancer properties. Laboratory and animal research has shown that resveratrol can act against cancer cells by activating or deactivating molecular pathways. It can help prevent the formation of potential carcinogens (substances that cause cancer), block the action of carcinogens on their target organs or tissue, and act on cells to suppress cancer development or induce apoptosis (programmed cell death). Despite their effectiveness against many cancers, current chemotherapy drugs often have serious side-effects and in some patients tumours develop ‘chemoresistance’. Laboratory studies have shown that resveratrol, and some other natural products, may be effective chemosensitisers – drugs that can be used to make chemotherapy more effective. Resveratrol can increase the sensitivity of some cancer cells to chemotherapy agents and overcome one or more of the body’s mechanisms that cause chemoresistance. By increasing antioxidant and anti-inflammatory activity, resveratrol may reduce side-effects of chemotherapy such as anorexia, fatigue, depression, neuropathic pain and cognitive impairment. However, some studies have shown that under certain circumstances, in some cancer types, resveratrol acts as a ‘chemoprotector’; it acts to protect cancer cells against chemotherapy agents and/or increase the number of cancer cells. There is also evidence that resveratrol may be toxic to some normal cells as well as cancer cells.