The Authors followed 29 patients, hospitaled with a diagnosis of pancreatitis. They all presented the same sympotomatology and a considerable increase of the serum amylase ad urinary amylase. The examination of the ratio between the clearance of amylasis and creatinine permitted to make a differential diagnosis for 8 cases (4rd group) that were nothing but peptic ulcera. Such a diagnosis was confirmed by the radiological contrastographic examination or by the intraoperative report. So if the ratio between the clearance of amylase and creatinine is normal we must think about a pathological situation were the iperamylasemia has a pathogenetic cause different from pancreatitis.