The aim of the present study was to ascertain the pharmacoeconomical efficacy of a clinical pathway (CP) employing medication management and instruction tasks (i. e. pharmaceutical care and counseling for inpatients) in gastrectomy patients. Pharmaceutical services of a uniform quality were provided. These included a CP check sheet, medication management, and a history of the drugs chiebly prescribed by pharmacists. As a result, the average number of hospitalized days among the patients who were offered pharmaceutical care compared with those who were not was significantly shortened from 35.4 days to 26.1 days (P<0.001). Moreover, the average cost of medication was also significantly reduced from 270,631 yen to 190,331 yen (P<0.05). These data provide the first evidence that a CP employing medication management and instruction tasks for gastrectomy patients may play a substantial role in saving on medical costs.