Bile salts and phospholipids from bile of chicken, dog, sheep, rat, ox, pig, guinea-pig and man were analyzed by high-performance liquid chromatography. Bile salts showed marked differences in their hydrophilic properties, owing to hydroxyl structure and type of conjugation. Phospholipids were generally similar, containing 90-95% of phosphatidylcholine which was made of molecular species containing palmitic acid in the sn-1 position. The comparative analysis of bile salts and phosphatidylcholines profile demonstrated that bile salts hydrophilicity influences the quantity of phosphatidylcholine in bile but not the quality.