This study shows that human bile, at a concentration in the range of that found in the intestinal lumen, inhibited the hydrolysis of emulsified triolein by pancreatic lipase in vitro. The addition of colipase in excess to lipase failed to restore lipolytic activity. In contrast, a partially degraded emulsion of triolein containing diacylglycerol, monoacylglycerol and free fatty acid was hydrolysed by lipase and colipase in the presence of bile. The results presented in this paper allow to conclude that triacylglycerol digestive products associated with emulsified lipid played an important role in the intraluminal degradation of dietary fat by pancreatic lipase and colipase in the presence of bile.