It is well known that chloramphenicol is readily absorbed from the gastro-intestinal tract, and appears in the blood shortly after oral administration. Its presence in the bile after an interval of two hours has been reported by Gruhzit, Fisken, Reutner, and Martino (1949), by Glazko, Wolf, and Dill (1949), and by Long, Bliss, Schoenbach, Chandler, and Bryer (1950). In the following paper some details are given of its excretion in the bile. METHODSAbsorption from the Portal Vein by the Liver.-After a 12-hr. fast, dogs of 8 and 13 kg. were given 80-100 mg. of chloramphenicol by mouth in a sufficient quantity of water. Half an hour later the abdomen was opened under chloralose anaesthesia, and blood samples were taken from the portal and hepatic veins.Excretion in the Bile of Dogs.-After ligation and section *of the common bile duct a biliary fistula was established. The general condition of the dogs remained good for a long period, for, by licking and swallowing some of the escaping bile, they obtained a 1024 a considerable quantity by mouth. The fistula was catheterized daily with a glass 512 catheter to maintain patency. The bile flow was continuous, indicating bile of 256-hepatic and not gall-bladder origin. About E a month after operation the fistula was well m 128-organized and no bleeding followed a catheterization.O 64-In each experiment chloramphenicol u was administered by stomach tube or oral Z 32-syringe, and at the same time a rubber I catheter was inserted ihto the fistula. E 16-Bile was flowing continuously, and blood C and bile samples were collected at intervals°8-after administration. The chloramphenicol I estimations were made by the colorimetric 4-method described by Bessman and Stevens (1950).2-Excretion in Human Bile.-A dose of 1 250 mg. was given to a man weighing 46 kg. with a post-operative biliary fistula: blood and bile samples were collected after