Seventy-one adults who were hospitalized between March 1985 and March 1987 were entered into a randomized, double-blind study to compare the efficacy and safety of furazolidone and chloramphenicol in therapy for typhoid fever. Patients received chloramphenicol capsules (total daily dosage, 2 g) plus placebo tablets for furazolidone tablets (total daily dosage, 800 mg) plus placebo capsules for 14 days. Seven patients were excluded from the analysis of efficacy because blood, bile, or bone marrow cultures at admission failed to demonstrate the presence of Salmonella typhi. Four additional patients were excluded because of intercurrent illness or failure to return for follow-up visits. Cure was achieved in 31 (97%) of 32 chloramphenicol recipients and 24 (86%) of 28 furazolidone recipients. In the chloramphenicol group, one patient experienced moderate sideroblastic anemia, and another experienced moderate neutropenia. Both adverse reactions resolved spontaneously within 7 days. Mild gastritis was reported by two patients who received furazolidone and one who received chloramphenicol. This study has demonstrated that furazolidone is an effective and safe alternative to chloramphenicol for the treatment of typhoid fever in adults.