Acomplia tablets contain the active ingredient rimonabant, which is a type of medicine called a cannabinoid-1 receptor antagonist. It is used to aid weight loss in people who are obese or overweight. Rimonabant works by blocking receptors called cannabinoid-1 receptors (CB1). These are found in the brain, fat tissue, digestive system, liver and muscles. The CB1 receptors are part of a system in the body called the endocannabinoid system. This system has only recently been discovered and explored. It is involved in regulating energy balance, sugar and fat metabolism and body weight. The CB1 receptors found in a particular area of the brain called the mesolimbic system are involved in controlling our intake of highly palatable, sweet or fatty foods. Overactivation of the CB1 receptors is associated with increased appetite, cravings for food and fat build-up.