Background. The role of the pharmacist has evolved over the last 2 decades beyond traditional functions such as stock control and dispensing. Objectives. To describe the functions performed by a clinical pharmacist while based in a surgical and trauma intensive care unit of a teaching hospital. Methods. An operational research study that included indications of programme success was conducted. Interventions to assess therapy and achieve definite outcomes to satisfy patients' medicine needs were documented for 51 patients over a study period of 8 weeks. Results. A total of 181 interventions were suggested by the pharmacist, with 127 (70%) accepted and implemented by the medical and nursing staff of the unit. The most frequent interventions were related to: untreated medical conditions (15.5%), appropriate therapy or course (13.8%), investigations indicated or outstanding (12.2%), and inappropriate doses and dosing frequency (11%). Interventions were also made regularly to address system errors or non-compliance and factors hindering therapeutic effect. Of the 250 h the pharmacist spent in the ward, most time was used for pharmaceutical care (28%) and ward rounds (21%) with members of the multidisciplinary team. Conclusions. The study results demonstrated that a clinical pharmacist's contribution to patient care at ward level resulted in improved monitoring of pharmacotherapy. Medicine-related problems were identified and addressed.