The use of herbal medicines by people with cancer in the UK: a systematic review of the literature

Design and Methods: Fifteen electronic databases were searched. People who were research-active in the field were contacted and asked about further published or unpublished work. All studies identified as relevant to the purpose of the review were assessed. Searches were not restricted by publication type or date. Results: Of 1288 unique references identified, 11 met the eligibility criteria. Studies were excluded where research had been conducted outside the UK; where information on herbal medicine use was not differentiated from that relating to complementary and alternative therapies more broadly, and where neither prevalence of use nor information on user characteristics was included. Prevalence estimates ranged from 3.1 to 24.9%. Most studies did not obtain information specifically on herbal medicines and only one examined the characteristics and motivations of users of herbal medicines as distinct from complementary and alternative therapies in general. Conclusions: The high degree of heterogeneity of methodology, sample selection and characteristics, and research design resulted in a wide range of estimates of prevalence. Well-designed research is needed to define the evidence base about the herbal medicines taken by people with cancer in the UK, the reasons for use, knowledge about possible effects and potential risks, and where people seek information.