Ward-based pharmacy interventions are effective for proper medical management. In Hiroshima University Hospital, clinical pharmacists participate in almost all inpatient cases. In addition to the regular clinical pharmacists for the 4 wards, a supervising pharmacist was allocated additionally to overview and to help them as a trial. The supervising pharmacist reviewed the prescriptions and assignments of physicians, and ordered authorized prescriptions. As a result, the number of drug-related incident reports for two months decreased from 17.3 to 3.0, compared to the number of reports of the past three years. The revision of prescriptions by a supervising pharmacist assembly might reduce the inspection workload and number of inquiries by the central pharmacy. On the questionnaire, 94％ of physicians expressed a decreased burden during this trial. Also a decreasing trend of overtime work of nursing staff was reported. Therefore, the allocation of a supervising pharmacist may contribute to medical safety and efficient work management of medical staff who are concerned with drug therapy.