Rimonabant is a novel drug for treatment of obesity. Four randomised studies have shown a significant effect of 20 mg rimonabant on bodyweight and other cardiovascular risk factors. The weight loss is modest, approximately 5 %, and the patients regain their baseline weight within 9 months after withdrawal. There is no evidence that rimonabant reduces morbidity or mortality, and no comparative studies with orlistat or sibutramine have been performed. Long-term effects of blocking the endocannabinoid system are not known. Side effects are nausea, depressive symptoms, anxiety and dizziness. There are reports on increased suicidality, and rimonabant is contraindicated in depressed patients.