The effects of emeriamine, a new anti-diabetic drug, on exocrine and endocrine pancreatic function in normal and diabetic rats have been studied both in vivo and in vitro. It was found that emeriamine dose-dependently normalized the symptoms of hyperingestion and hyperposia in streptozotocin (STZ)-induced diabetic rats, with fasting glucose levels significantly decreased and insulin levels not changed. In STZ-induced diabetic rats, there was a significant increase in pancreatic lipase and trypsin contents and a sharp decrease in amylase content. These changes in lipase and trypsin, but not in amylase were normalized by administration of emeriamine. In the normal rat, emeriamine had no effect on either serum glucose or insulin levels, but significantly decreased the pancreatic amylase, lipase as well as trypsin contents by 68%, 58% and 51%, respectively. In vitro, emeriamine (10⁻⁸-10⁻⁴ mol l⁻¹) had no effect on enzyme release from pancreatic acini either under basal or carbachol-stimulated conditions. Emeriamine inhibited glucose-induced insulin release from isolated pancreatic islets. In conclusion, emeriamine has an inhibitory effect on synthesis of pancreatic enzymes and on glucose-stimulated insulin release.