A significant proportion of cancer patients try unconventional therapies and many use 'complementary' therapies, as adjuncts to mainstream care, for management of symptoms and to improve quality of life. A smaller proportion use 'alternative' therapies, which are typically invasive, biologically active, and commonly promoted as replacements for, rather than adjuncts to, mainstream therapy. Many alternative therapies, including high-dose vitamin C, the Di Bella regimen, and laetrile have been shown not to be effective. For others, such as metabolic therapy, evidence is extremely limited. Conversely, most complementary therapies are well studied and of proven benefit. There is evidence from randomised trials supporting the value of hypnosis for cancer pain and nausea; relaxation therapy, music therapy, and massage for anxiety; and acupuncture for nausea. Such complementary therapies are increasingly provided at mainstream cancer centres.