The prevalence of obesity is increasing at an alarming rate and a plethora of complementary therapies are on offer claiming effectiveness for reducing body-weight. The aim of this systematic review was to critically assess the evidence from RCTs and systematic reviews of complementary therapies for reducing body-weight. Literature searches were conducted on Medline, Embase, Amed and the Cochrane Library up to January 2004. Hand-searches of relevant medical journals and bibliographies of identified articles were conducted. There were no restrictions regarding the language of publication. Trial selection, quality assessment and data abstraction were performed systematically and independently by two authors. Data from RCTs and systematic reviews, which based their findings on the results of RCTs, were included. Six systematic reviews and 25 additional RCTs met the inclusion criteria and were reviewed. The evidence related to acupuncture, acupressure, dietary supplements, homoeopathy and hypnotherapy. Except for hypnotherapy, Ephedra sinica and other ephedrine-containing dietary supplements the weight of the evidence was not convincing enough to suggest effectiveness. For these interventions, small effects compared with placebo were identified.