Pancreatic function was assessed prospectively in a group of 18 treated adult coeliac patients, most of whom were asymptomatic. The para-aminobenzoic acid (PABA) test indicated exocrine pancreatic insufficiency in three patients, all of whom had persisting gastrointestinal symptoms. Arginine, 5 g intravenously, was used to stimulate pancreatic islet cells; basal and stimulated concentrations of plasma insulin, C-terminal glucagon, N-terminal glucagon, and blood glucose did not differ from asymptomatic nondiabetic control subjects. After gluten withdrawal, coeliac patients who responded clinically had no evidence of significant pancreatic impairment, but consideration of exocrine pancreatic insufficiency is worthwhile in those patients with persisting symptoms.