Background: Drug-related problems (DRP) can arise between the time a drug is prescribed until it has an effect on the patient. The present study describes the methodology used in our hospital to identify, prevent and resolve DRP. The main objective of this study was to determine the prevalence and characteristics of the DRP detected and the results of the pharmaceutical interventions performed to resolve these events. Material and methods: DRP were analyzed during a 1-year period in a general 450-bed hospital with a unit-dose drug distribution system (UDDDS) in all beds. A pharmacist reviewed all drugs processed in the UDDDS daily. When a DRP was identified, the therapeutic recommendation was communicated in writing through standard form, and the response obtained after 48 hours was registered. Results: During the study period, there were 17180 admissions and 4859 DRP were detected. The highest percentage of DRP (54%) corresponded to drugs not included in the drug formulary and 88% of these DRP were due to drugs that could have been substituted for drugs included in the drug formulary. Another important group of pharmaceutical interventions corresponded to drug interactions, recommendations on drug administration, allergy alerts, and indications for pharmacotherapeutic monitoring. The most frequently involved drugs were those acting on the cardiovascular system. A total of 41.7% of pharmaceutical interventions were accepted. Conclusions: The application of the program proposed was useful for detecting, preventing and resolving DRP. Given the repercussions of DRP, a standardized system that would allow follow-up of drug treatment is required.