Each of 19 patients undergoing the acute febrile phase of Carrión's disease received, in divided doses, approximately 17.0 gm. oral chloramphenicol in five days. After initial dosage with chloramphenicol, temperature usually returned to normal within 24 hours. A reticulocyte response averaging nine per cent (varying between 6.8% and 36%) was evident shortly after the beginning of chloramphenicol therapy. Although some coccoid forms of the bartonellae remained in the red cells, the bacillary form disappeared in 24 hours. Red cell count and red cell size were reestablished. Relapse was infrequent; when it occurred, further administration of chloramphenicol resulted in recovery.
Three of the patients were also infected with Salmonella; one of these died, the other two made a gradual recovery. Since Carrión's disease and a Salmonella infection are likely to co-exist, chloramphenicol is suggested as the drug of choice to combat both the bartonellosis and the complicating salmonellosis. Large doses of chloramphenicol had no depressing influence on blood formation.