Seven patients were investigated after cholecystectomy and exploration of the common bile duct to determine bile composition and excretion rates. An initial depression of the major components of bile stabilized by the sixth postoperative day. Feeding of para-aminobenzoic acid and taurocholic acid to these patients demonstrated an increase in excretion of total bile acids, taurine and glycine conjugates, cholates and deoxycholates. Para-aminobenzoic acid in the doses used failed to block glycine conjugation. Preferential conjugation of bile acid with glycine is due to a deficient taurine pool and not a preferential metabolic pathway.