Glucagon-like peptide-1-(7-36) amide (GLP-1) is an incretin hormone of the enteroinsular axis. Recent experimental evidence in animals and healthy subjects suggests that GLP-1 has a role in controlling appetite and energy intake in humans. We have therefore examined in a double-blind, placebo-controlled, crossover study in 12 patients with diabetes type 2 the effect of intravenously infused GLP-1 on appetite sensations and energy intake. On 2 days, either saline or GLP-1 (1.5 pmol. kg-1. min-1) was given throughout the experiment. Visual analog scales were used to assess appetite sensations; furthermore, food and fluid intake of a test meal were recorded, and blood was sampled for analysis of plasma glucose and hormone levels. GLP-1 infusion enhanced satiety and fullness compared with placebo (P = 0.028 for fullness and P = 0.026 for hunger feelings). Energy intake was reduced by 27% by GLP-1 (P = 0.034) compared with saline. The results demonstrate a marked effect of GLP-1 on appetite by showing enhanced satiety and reduced energy intake in patients with diabetes type 2.