Two cases of moderate neutropenia and 3 cases of severe neutropenia in the course of fusidic acid treatment for sepsis related to a hip prothesis or septic osteitis are reported. Neutropenia was always observed following routine blood cell count, after a mean of 21 days' treatment (16 to 27 days). Moderate fever was observed only once, in a patient with profound neutropenia. A complete recovery of blood cell count was noted in all cases, 5 to 9 days upon discontinuation of fusidic acid. A sternal bone-marrow aspiration was performed in 4 cases, showing normocellularity or hypercellularity in two cases, and moderate hypoplasia of granulocytic cells. The respective roles of other treatments are discussed. Overall, these five cases suggest that reversible granulocytopenia can be caused by protracted treatment with fusidic acid. Although nine different associated drugs could also have been involved in four patients, the causal relationship was less suggestive for three of them due to chronological events. In other cases, the drugs never or very rarely caused neutropenia. Finally, the possibility of vancomycin-induced neutropenia cannot be excluded in one case.