The clinical pharmacology of chloramphenicol was evaluated in 14 children with serious bacterial infections. The children received chloramphenicol sodium succinate intravenously for five to six days at which time orally administered chloramphenicol palmitate was substituted for an additional five to six days of therapy. The mean peak serum chloramphenicol concentration when given iv (28.2 +/- 5.1 micrograms/ml) occurred within one hour after the termination of the 60-minute iv infusion and when given orally (19.3 +/- 2.6 micrograms/ml) occurred two to three hours after ingestion. Differences in serum levels of chloramphenicol after iv compared to oral administration of the same dose could be demonstrated at various time points studied during the dose-response curves; however, the areas under the chloramphenicol curve were not significantly different after iv (140 +/- 116 micrograms/ml/hour) versus oral (95 +/- 26 micrograms/ml/hour) administration. In seven patients who had concomitant serum and CSF chloramphenicol levels determined, a CSF to serum ratio of 23 to 85% occurred. The CSF levels (5.5 to 13 micrograms/ml) were not directly proportional to serum levels. All patients recovered from their infection and no side effects from chloramphenicol were encountered. Administration of chloramphenicol orally in the palmitate form produces serum concentrations and areas under the disappearance curve similar to those achieved after iv administration of the same dose, indicating that the oral route is an effective method of achieving therapeutic concentrations of chloramphenicol in serum.