The cannabinoid-1 (CB1) receptor plays a role in the regulation of appetitive behavior. Exogenously administered cannabinoid receptor agonists stimulate food consumption in animals and humans. Endogenous cannabinoid receptor agonists are present in the brain, and the brain level of these agonists increases with greater demand of food by rodents. Specific CB1 receptor antagonist compounds have been discovered that display high affinity and selectivity for the CB1 receptor. CB1 receptor antagonists inhibit both acute and long-term food intake in rodents. Chronic treatment with CB1 antagonists results in a sustained reduction in body weight in rodents (5 weeks), and weight loss in humans (16 weeks). Patent literature indicates CB1 receptor antagonist discovery efforts at a number of pharmaceutical companies. The CB1 receptor antagonist, rimonabant (SR-141716), discovered by Sanofi-Synthélabo, is in phase III clinical trials for the treatment of obesity and has been found to decrease appetite and body weight in humans.