AIM: The aim of this project was to establish the importance of a pharmacist in the health-care team in improving drug use in an oncology ward in the Department of Oncology, Karolinska University Hospital, Stockholm, Sweden. METHODS AND PATIENTS: The pharmacist participated in the medical round in the mornings and worked as a member of the health-care team. Drug-related problems (DRPs) were identified by drug chart reviews based on data from medical files, laboratory tests and interviews with patients and/or relatives. A questionnaire to physicians and nurses was used to evaluate their experiences of the pharmacist's contribution to the oncology ward. RESULTS: In total, 114 DRPs were identified in 58 patients. For each DRP, the pharmacist gave proposals for solutions. Sixty-eight suggestions out of 114 (59.6%) were implemented by the physician. Two suggestions (1.8%) were partly followed. For 32 suggestions (28.0%) it was unclear if they had caused any change in medication. Twelve suggestions (10.5%) were not followed. Most of the physicians and nurses acknowledged the pharmacist's contribution to improved drug use in the ward. CONCLUSION: A pharmacist can improve drug use in an oncology ward as a member of the health-care team. The pharmacist contributes with a systematic focus on the patient from a drug perspective.