Only two drugs are currently approved for long-term use in the treatment of obesity, and four others for short-term use. Evaluating the risk-benefit profile is an essential first step. For individuals who have a low body mass index for whom the risk is small, the risk profile must make the drug acceptable for almost everyone. For higher-risk patients, such as those planning intestinal bypass or who have sleep apnea, a wider range of drugs may be considered. Obesity is a chronic disease that has many causes. Treatment is aimed at palliation—that is, producing and maintaining weight loss. Regardless of the primary site of action, the net effect must be a reduction in food intake or increase in energy expenditure.