The report by Gumaste et al. [Gastroenterology 1991;101:1361–1366] that the lipase/amylase ratio (Lip/Amy) could be a new index distinguishing acute episodes of alcoholic (Lip/Amy >2) from nonalcoholic pancreatitis (Lip/Amy <2), with the critical value being Lip/Amy =2, has been followed by some debate between supporters and opponents. By comparing the Lip/Amy in a group of 16 carefully selected patients with mild acute gallstone-related (biliary) pancreatitis with that in a reference group of 44 controls, this study examines whether or not this ratio could be a useful index for diagnosing biliary pancreatitis. Considering that both pancreatic and hepatobiliary systems are blocked by stones, hepatic biochemical parameters such as serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and total bilirubin (TB) were also included in fitting the regression equation. The average value of Lip/Amy in the biliary pancreatitis group was 2.29 ± 0.93, while that in the control group was 1.30 ± 0.99. Thus, Lip/Amy was found to be a significant index for distinguishing mild acute biliary pancreatitis from nonpancreatitis. However, the critical value of Lip/Amy seemed to depend on the diet pattern and cultural background.