In accepting any new drug for the treatment of obesity, the safety profile must make it acceptable for almost everyone. Criteria for selecting treatments involve evaluating the risks to the individual from obesity and balancing that against any possible problems with the treatment. Obesity is a chronic disease that has many causes. Cure is rare and treatment is thus aimed at palliation, that is, producing and maintaining weight loss. Wherever the primary site of action may be, however, the net effect must be a reduction in food intake or an increase in energy expenditure.