Exocrine pancreatic function was assessed in 588 subjects by oral administration of 1 g of the chymotrypsin-labile peptide N-benzoyl-L-tyrosyl-p-aminobenzoic acid (Bentiromide) from 1974 to 1979. The pancreatic function test (PFT) was performed in 126 controls, 217 patients with pancreatic diseases, 196 patients with various non-pancreatic gastrointestinal disease, 18 patients with renal disease and 31 patients with various other diagnoses. In 62 of 72 patients (86 per cent) with chronic pancreatitis and in 19 of 25 (76 per cent) with pancreatic carcinoma, the excretion of p-aminobenzoic acid (PABA) in the urine was significantly less than in the controls. In contrast, 328 of 353 controls and patients with non-pancreatic diseases (93 per cent) had PABA excretion within normal limits. The sensitivity and specificity of the Bentiromide-test observed in this study is sufficient to detect moderate to severe disturbances of pancreatic exocrine function. The PFT has proved to be an easy and reliable screening test for pancreatic exocrine function in ambulatory as well as in hospitalized patients.