The synthesis of 19-hydroxylated bile acids (3 alpha,19-dihydroxy-, 3 alpha,7 alpha,19-trihydroxy-, 3 alpha,12 alpha,19-trihydroxy- and 3 alpha,7 alpha,12 alpha,19-tetrahydroxy-5 beta-cholan-24-oic acids) was described. These synthesized 19-hydroxylated bile acids were used as standard samples for the analysis of bile acids in human urine by gas chromatography-mass spectrometry. 3 alpha,7 alpha,12 alpha,19-Tetrahydroxy-5 beta-cholan-24-oic acid was identified in neonatal urines (0.1-1.5 micrograms/ml and 1.5-7% of total bile acids).