This chapter provides an overview of the distribution and supply of medicines in primary and secondary care, and considers how some of the routine datasets have evolved, and their uses. In the UK, drugs are classified principally according to their actions and side effects into different legal classifications through the Medicines Act. These classifications control the public's access to medicines and also define how medicines are distributed and supplied. In the community setting, the traditional route of supply of 'prescription only medicines' to the public has been if a doctor, or for a limited range of drugs a dentist, has prescribed them. In the hospital setting, medicines are prescribed by doctors and supplied by the hospital pharmacy department. Pharmacy managers have been able to compare drug usage and expenditure patterns between consultants and specialties and also within specialties over time. Those that take medicines also need information.