Because it is thought that chloramphenicol is poorly absorbed after intramuscular administration, we compared blood levels of chloramphenicol after intramuscular administration with those after intravenous administration in children with a variety of diagnoses. Fifty-seven children were studied on 62 occasions while they were receiving chloramphenicol sodium succinate (25 mg of chloramphenicol per kilogram of body weight) intramuscularly every six hours. The peak level of chloramphenicol was 19.5 +/- 5.99 micrograms per milliliter (mean +/- S.D.) in 11 children after the first dose and 31.4 +/- 12.99 micrograms per milliliter in 51 children after two or more doses. The lowest peak level after intramuscular administration was 13 micrograms per milliliter, which is in the therapeutic range of 10 to 30 micrograms per milliliter. Thirteen children were studied on 17 occasions while they were receiving chloramphenicol sodium succinate (25 mg of chloramphenicol per kilogram) intravenously every six hours. The peak level of chloramphenicol was 19.4 +/- 6.37 micrograms per milliliter in eight children after the first dose and 28.2 +/- 11.09 micrograms per milliliter in nine children after two or more doses. The area under the serum level curve was not significantly different after intramuscular and intravenous administration. We conclude that chloramphenicol sodium succinate is well absorbed after intramuscular administration. This route is cheaper, it demands less staff time, and it does not carry the risks of sepsis and overhydration associated with intravenous therapy.