BACKGROUND AND OBJECTIVE: Due to drug-related problems (DRPs) that cause both unnecessary suffering and huge costs to society, many patients do not receive the intended beneficial effects of their treatment. Pharmacy practitioners have a key responsibility to respond to these problems, but more knowledge about the expected outcomes of their interventions is needed. The objective of the study was to assess the clinical and economic outcomes of community pharmacy interventions in patient DRPs. METHODS: Drug-related problems in 13 different patient groups were identified and classified, according to the Westerlund System, by pharmacy practitioners from 89 Swedish pharmacies in 2006. The cases were documented in the pharmacy software and transferred to the national DRP database. An assessment model was developed and applied by the researchers (a pharmacist and a physician). This assessment was used to conduct a retrospective review by analysing the DRP and intervention documentation, in particular case descriptions from free text fields. Expected clinical patient outcomes of pharmacy interventions were judged in terms of improved therapeutic effects and prevented or relieved adverse drug reactions (ADRs). The review also assessed the expected patient outcomes with regard to initiated or avoided primary care contacts or avoided hospitalisations. The resulting hypothetically avoided direct societal costs and the estimated pharmacy personnel costs were calculated for the study and extrapolated to the Swedish nationwide level on an annual basis, to demonstrate the potential of national cost savings by pharmacy DRP-interventions. RESULTS AND DISCUSSION: In 358 cases (68%), the pharmacy interventions were judged to have produced an improved therapeutic effect in the patient, and in 172 cases (32%) to have prevented or relieved ADRs. Primary care contacts were initiated for 151 patients (29%), and pharmacy interventions were assessed to have saved 68 (13%) primary care contacts and 16 (3%) future hospitalisations. The potential societal cost savings extrapolated to Sweden at the national level were estimated at euro 358 million. This is 37 times the expected pharmacy personnel costs for identifying and responding to the DRPs. CONCLUSION: Our study demonstrates that community pharmacy interventions in patient DRPs are most likely to lead to favourable clinical and economic outcomes. The convincing cost-benefit ratio should be presented to health care politicians and decision makers to encourage appropriate remuneration for these services.