The role of gastrin-like peptides in a regulation of feeding behaviour was studied in a snail Helix lucorum. Sensory stimulation during 15 min carried out by a patch of clothes moistened by the carrot juice (pseudo-feeding) decreased the weight (by 25-50%) of eaten carrot and the duration of the food intake. Similar satiety effect was found after pentagastrin (380 ng) or cholecystokinin-octapeptide (560 ng) injection 20 min after the beginning of the food intake. Measurement of the gastrin-like immunoreactivity showed that the peptide levels in the meta-cerebral ganglia and the haemolymph were dependent on the stage of feeding behaviour. After pseudo-feeding the peptide levels in the ganglia and the haemolymph were significantly higher than those during feeding. Our results suggest the presence of a single gastrin/cholecystokinin-like peptide with feeding stage-dependent functional significance in Helix snails.