The investigation was performed on 8 sheep with implanted catheters in the common bile duct and in the cystic duct. Sodium taurocholate and sodium dehydrocholate were infused into the jugular vein at the rate of 50 mumol/min for 20 min. Directly after the termination of the sodium taurocholate infusion, the volume of the secreted bile increased from 8.4-9 microliters.kg-1.min-1 to the highest mean value of 17.8 microliters.kg-1, min-1, with a simultaneous increase in the concentration of cholates from 1.71 mmol/l to 4.82 mmol/l and bilirubin from 271.1 mumol/l to 461.7 mumol/l. The concentration of cholesterol and phospholipids in the bile also increased, but did not reach statistically significant values. The infusion of sodium dehydrocholate caused an increase in the bile secretion to the highest mean value of 20.59 microliters.kg-1.min-1 with a simultaneous decrease in the concentration of bilirubin to 148.75 mumol/l, cholesterol to 233.0 micrograms/ml, phospholipids to 56.11 micrograms/ml and cholate to 1.0 mmol/l. The results show that biliary secretion of phospholipids, cholesterol and bilirubin is dependent on the secretion of sodium taurocholate rather than on dehydrocholic acid.