The ability of a novel chitosan formulation to influence gastrointestinal fat absorption in vivo was examined in a double-blind, placebo-controlled, crossover study by determining the content of total fat in feces in two groups of subjects. Twenty-nine normal healthy subjects were recruited for the study. Twenty-four participants completed the test period with the chitosan formulation, and 21 completed the placebo phase of study. During the placebo and the test periods, the subjects were administered six capsules three times daily 10 minutes before meals for three days and for the two days of the stool collection. A daily serving of six tablets of the test compound contained 2100 mg chitosan and 300 mg psyllium husk seeds. In respect to the baseline period, the test compound increased fat excretion significantly whether the test period preceded or proceeded the placebo period (p<0.02 and p<0.05 respectively). In contrast, essentially no changes were seen during the placebo loading periods. Compared to the difference between placebo period and its baseline period, a statistically significant increase in fecal fat excretion was observed over baseline following oral supplementation of a novel formulation of chitosan and psyllium husk seeds [+3.63 gm/day +/- 0.83 (SEM) vs. -0.15 gm/day +/- 0.94 (SEM) (p=0.004)]. The average daily increase in fecal fat of 3-4 grams over control could account for a decrease in calorie consumption of 30-40 kcal per day. A total of 19 subjects completed both parts of the study. Examining the data from these 19 subjects by ANOVA, it was found that the period when the test compounds were given was statistically significantly different from the placebo baseline, placebo experimental, and test baseline periods. Using multiple comparisons, it was ascertained that the novel formulation containing chitosan plus psyllium husk seeds increases fecal fat excretion.