Guerciolini et al.compared chitosan and orlistat to determine their effect on fat absorption. Twelve healthy volunteers (within 20% of their ideal body weight) participated in this 14-day openlabel crossover study consisting of a one-week runin period, one week of treatment with orlistat 120 mg three times daily, and one week of treatment with chitosan 445 mg three times daily. The participants consumed standardized diets of 2500 kcal/day throughout the trial, and fecal samples were collected during the run-in and treatment periods. Orlistat produced a significant increase in mean ± S.D. fat excretion from baseline (1.36 ± 0.45 g/day versus 16.13 ± 7.27 g/day). However, chitosan had no significant effect on fat excretion (1.36 ± 0.45 g/day versus 0.27 ± 1.02 g/day). The chitosan recipients noted fewer gastrointestinal adverse effects (8%) than the orlistat group (66%) (p not reported).