The influence of calcitonin on the choleresis level and bile acids spectrum was investigated in acute experiments on the rats with common biliary duct cannulated. We determined the intensity of bile secretion during 3 hours and quantitative content of conjugated and free bile acids using thin-layer chromatography. It was shown that intramuscular introduc­tion of synthetic salmon calcitonin (200 ng/kg) increases the secreted bile volume and the content of conjugated bile acids in the bile. The administration of salmon calcitonin resulted in increase of bile volume (+17,4% (P<0.05)), taurotrihyd-roxycholates (+58,3% (P<.001)), taurodihydroxycholates (+68,5% (P<0.01)), glycodihydroxycholates (+120,8% (P<0.01)), while the total content of free bile acids was not significantly altered as compared with control. At the same time, under the hormone influence we observed bile acid spec­trum redistribution and a part of conjugated cholates increased against a decreasing of free bile acids part. The present results suggest that the salmon calcitonin intensifies the processes of conjugation of bile acids with amino acids taurine and glycine in hepatocytes and canalicular secretion that results in improvement of solubilization properties of the bile, ability of the bile to hold cholesterol in solute state and prevent the formation of calculi in biliary tracts.