The present study investigated the effect of alprazolam on the pattern of food intake in seven male participants living in a residential laboratory for 17 days. A wide selection of meals, snacks and beverages was freely available. Capsule administration occurred at 1300 and 1730 hours. Food intake on days when alprazolam (0.75 mg) was administered (days 2, 11) was compared to days when no capsule (days 1, 9) or placebo (days 3, 10) was administered. Alprazolam increased total caloric intake by approximately 975 kcal from a baseline of 2800 kcal. Alprazolam increased the number of eating occasions occurring in the evening (1700-2330 hour), without altering the size of eating occasions (kcal), or the proportion of total calories derived from carbohydrate, fat and protein. These data demonstrate alprazolam's robust effects on food intake in humans.