Trypsin-like activity is released after stimulation of the exocrine pancreas. We investigated under basal conditions and after stimulation by a meal whether patients suffering from pancreatic disorders differ with respect to plasma trypsin-like activity (PTLA). In 45 subjects (healthy volunteers: n = 18, mild/moderate alcoholic chronic pancreatitis: n = 16, nonjaundice pancreatic cancer n = 7, and calcifying chronic pancreatitis: n = 4), basal and postprandial levels of PTLA were measured over a period of 2 hours. Basal plasma levels were similar in the first 3 groups. After stimulation, healthy volunteers and patients with pancreatic cancer showed significant decreases in trypsin-like activity; however, plasma levels did not decrease in patients with mild/moderate chronic pancreatitis (P < .001). Healthy individuals demonstrate a consistent decrease in postprandial trypsin-like plasma activity. This response is not altered in patients with pancreatic cancer, and it is not seen in patients with mild/moderate alcoholic chronic pancreatitis.