Initially used to measure algic symptoms, visual analogue scales (VAS) can also be useful for the evaluation of satiety. The antiobesity agent sibutramine, unlike anorectic agents, decreases food intake mainly by stimulating satiety. To evaluate the effect of sibutramine on satiety, we used a VAS in obese adolescents participating in a double-blind, randomized trial comparing 10 mg of sibutramine to placebo. Each patient received 13 scales to be checked at hourly intervals, in a single day, from 9 am to 9 pm. A 500 kcal deficit diet was divided into 3 meals, with previously fixed times: 9:30 h, 12:30 h, 18:30 h. Using the scores obtained from each scale, a line graph was designed to represent the average satiety score throughout the day. Comparing the area under the curve for the 2 groups, we found 4.609 +/- 1.309 for the group treated with sibutramine and 4.141 +/- 1.432 for the placebo group, not reaching statistical significance (p= NS). Therefore, sibutramine does not seem do have an effect on satiety of obese adolescents, at least when satiety is evaluated by a VAS.