Pancreatic function in Crohn's disease. We investigated exocrine pancreatic function in a population of patients with Crohn's disease in order to correlate the pancreatic function with clinical and laboratory variables. A total of 143 patients affected by Crohn's disease and 115 control subjects were studied. All had a Lundh meal test. As a group patients with Crohn's disease had significantly decreased activity of both amylase (p less than 0.02) and lipase (p less than 0.001) in duodenal aspirates. In patients with Crohn's disease enzyme activities were not correlated to duration of disease or to extent or localisation of previous bowel resection. The lowest enzyme values were found in patients with the most extensive bowel involvement, and they were significantly lower (p less than 0.05) than in patients with disease confined to the terminal ileum. The differences between enzyme values in other subgroups of patients were not significant. For the patient group as a whole no correlation was found between disease activity and enzyme values, but for the most uniform group of patients, those with terminal ileitis, pancreatic function was significantly lower (p less than 0.05) in patients with moderate and severe disease compared with patients with mild disease. Thus at least two factors seem to be responsible for impaired pancreatic function in Crohn's disease: firstly disease activity and secondly localisation or extent of disease. 