Since octreotide (SMS 201–995, Sandostatin; Sandoz Pharmaceuticals) is a potent inhibitor of pancreatic exocrine secretion and gallbladder contraction, long-term treatment with this drug may theoretically result in impaired pancreatic function and gallstones. However, we observed excellent pancreatic exocrine function – as assessed by the PABA/PAS test – in acromegalics who received octreotide treatment for more than 6 months. Plasma cholecystokinin showed a significant, although blunted, postprandial response, which exceeded the threshold for gallbladder contraction in healthy controls. Remarkably, postprandial gallbladder contraction was completely abolished for at least 2 h during octreotide treatment. In contrast to other studies, none of 16 acromegalic patients on long-term octreotide treatment developed gallstones. Although the incidence of gallstones in patients on long-term octreotide treatment may be increased, the risk seems to be variable.