Objective: This study was conducted with four objectives in mind, including: (1) characteristics of selfmedication; (2) storage of drugs at home; (3) factors associated with storage of drugs at home; and (4) comparison of the level and sources of knowledge between over-the-counter (OTC1) and prescription-only (POM2) medication consumers. Methods: A cross-sectional survey was conducted in 2007 using a semi-structured questionnaire on 300 clients of 21 drugstores (from a total of 214 drugstores in the city of Tabriz, Iran). Results: The highest demand for drugs was for analgesics (from OTC drugs) and antibiotics (from POM drugs). Of 325 requests for medications by 300 customers of drugstores in Tabriz, aged 15 years or higher, 50.8% (165 requests) were for OTC drugs and 49.2% (160 requests) were for POM drugs, twenty-five cases requested both OTC and POM medications. There were 246 customers (82%) who reported that they stored drugs at home. Physicians were reportedly the most common source of information about medications, while the highest-quality information was obtained from pharmacists. Conclusion: The frequency of home storing of medications was very high in this study. Customers, especially the lower education groups, had very little information about the side effects of drugs and differentiation of OTC and POM medications. Wayward use of antibiotics was very high among the drugstore clients. It seems that the information provided by the pharmacists can be one of the most effective ways for advancing the level of knowledge among the consumers of medications.