Verapamil was studied for its effects on secretory function of liver in rats. In the animals with low initial level of bile secretion, infusion of verapamil resulted in increase of the bile flow conjugated with taurine bile salts and ester of cholesterol, and in reduction of the non-conjugated bile salts secretion, as well as bile salts conjugated with glycine. In the animals with high initial level of the liver secretory function, verapamil decreased the bile flow, the secretion of unconjugated bile salts, and bile salts conjugated with taurine and glycine, phospholipids, cholesterol and its ester. The changes of bile flow and biliary secretion of bile acids and lipids in two groups of animals suggest that verapamil could be influenced in regulation of bile secretion depending on its initial level. Possible mechanisms of the bile secretion regulation by verapamil, are discussed.