There is no agreement in the literature as regards the carrying out of the Secretin-Pancreozymin test in order to achieve the greatest accuracy in the diagnosis of pancreatic insufficiency. In this study the results obtained by bolus i.v. injection of Secretin and Pancreozymin GIH are compared with those obtained by i.v. infusion of the hormones. The test - always prolonged for one hour - was done in 125 subjects, divided into two groups matched for sex, age and pancreatic or digestive disease. Volume, pH, bicarbonates, calcium and amylase were measured in the juice collected. The results showed that bolus i.v. injection of Secretin and Pancreozymin has greater diagnostic sensitivity (94%) than the infusion method (84%). If infusion is used, it is necessary to protract the test for more than one hour.