ObjectiveNonprescription (over-the-counter) medications in Australia are classified as Pharmacist Only Medicines, Pharmacy Medicines, or unscheduled medications. This report characterizes these medication classifications using key sales and purchasing behavior variables. DesignDescriptive, nonexperimental, cross-sectional study. Setting15 pharmacies in southeast Queensland, Australia, with data recorded over 36 hours per pharmacy in mid-August, 2006. ParticipantsEligible purchasers (n = 3,470 medication purchases) of all nonprescription medications (including nutritional supplements). InterventionResearchers documented details of all observed nonprescription medication sales and interviewed all available patients following the transaction. Main outcome measuresIncidence of product-related consultation, products purchased (brand, dosage form, classification), and purchasing behavior data (including previous purchase, intended use, intended user, and intention to purchase a particular brand). ResultsMore restrictive classification of the purchased medication was significantly (P < 0.01) associated with younger purchasers, purchase of a single nonprescription medication, intent to self-use the medication, intent to purchase a particular brand, repeat purchase, brand-switching interventions by pharmacy staff, pharmacy staff influence on first-time purchases, and observed consultation by pharmacists. Legislative compliance issues were identified: Pharmacists consulted in only 54.7% of Pharmacist Only Medicine sales and 13 cases (1.7% of observed sales) occurred in which Pharmacist Only and Pharmacy Medicines had been sourced from publicly accessible areas of the store. ConclusionPharmacist Only Medicines received greater levels of professional involvement during their sale than Pharmacy Medicines and unscheduled medications, despite higher levels of product familiarity among patients. To optimize the benefits of this classification system, emphasis on professional guidelines is recommended.