This cross-sectional, descriptive study was carried out in Morelia, Mexico, to find out the extend to which the public was buying essential drugs and other pharmaceuticals whose sale is prohibited or strictly regulated in other countries, and to determine the magnitude of the practice of self-medication. Customers buying drugs at 54 pharmacies were interviewed during peak shopping hours. The mode of acquisition of the drugs was classified as self-medication, medical prescription, or prescription from pharmacy salesperson, and the drugs were grouped as essential or nonessential. Products that are prohibited or greatly restricted in other countries were also identified. The most frequently bought products were analgesics and nonsteroidal anti-inflammatory drugs, vitamins, broad-spectrum antibiotics, steroids, cold and flu medications, narrow-spectrum antibiotics, and benzodiazepines. Of 1388 products sold, 394 (28.4%) appear on the list of essential drugs. The mode of acquisition was self-medication for 51.4% of the sales, medical prescription for 35.6%, and recommendation of a pharmacy employee for 13%. In addition, 14.3% of the products bought were prohibited or restricted in other countries. The results highlighted the need for greater precision in the General Health Law of Mexico with regard to regulation of drug sales. The results also imply the need for other actions, namely, educational campaigns directed to the general population to discourage self-medication; Strengthening of coordination between government and the pharmaceutical industry; improvement in the availability of and information on generic drugs; and modification of pharmacological training programs.