The aim of the study was to test the efficacy of 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholanate as a blood-brain barrier (BBB) permeator by examining its effect on quinine uptake into the central nervous system in rats, analgesic action of morphine, and on the sleeping time induced by pentobarbital. The obtained results indicate that sodium 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholanate can be considered as modifier of BBB permeability, as it exhibited a promoting effect in all three tests. In the test of quinine uptake, methyl ester of 3alpha,7alpha-dihydroxy-12-oxo-5beta-cholanoic acid (included in the study for comparison) did not show a promoting effect, which can suggest its specific action.