This study evaluates the use of orlistat, a lipase inhibitor, in the treatment of obese adolescents. In conjunction with a reduced-calorie diet, exercise, and behavioral modification, treatment with 120 mg of orlistat 3 times daily for 52 weeks statistically significantly decreased BMI, waist circumference, and body fat compared with placebo. This effect is probably due to the decrease in the absorption of fat and its associated calories.24 Gastrointestinal tract adverse effects were observed more frequently with orlistat. In these 352 adolescents studied over a 1-year period, no major safety issues were raised.