A randomized trial was performed to support the contention that prophylactic antibiotics can reduce the incidence of postoperative neurosurgical wound infections. The regime outlined by Malis was followed. Vancomycin and gentamicin were administered systemically just prior to surgery and streptomycin was added to the irrigating solution. Patients were randomly assigned to two groups: control and treated. The infection rate in the control group was 3.5% and in the treated group 0.5%.