Chloramphenicol is a broad spectrum antibiotic isolated from the soil bacterium Streptomyces venezuela (22). It is bacteriostatic in action and inhibits bacterial protein synthesis by binding to the ribosomal 50S (23) subunit. Chloramphenicol has been used to treat a wide range of human and animal conditions. Chloramphenicol is well absorbed orally and is distributed widely in body fluids. It is metabolized in the liver to the inactive glucuronide. Both chloramphenicol and the glucuronide metabolite are excreted in urine. Metabolism studies in food producing animals demonstrated numerous differences in metabolic profiles between bovine, porcine and poultry species, although the parent drug was the major metabolite identified in muscle for all species.