This chapter reviews some key issues in the history of drug regulation, then summarises the main regulations which now affect medicines, their distribution and supply. Medicines are classified in three categories in the UK: prescription only medicines (POM), pharmacy medicines (P) and General Sales List (GSL) medicines. Medicines in each of the above categories are issued with 'marketing authorisations' or 'product licences' by the Medicines and Healthcare Products Regulatory Agency or by the European Agency for the Evaluation of Medicinal Products. The advertising of medicinal products is controlled by the Medicines Act 1968 and the Regulation made under it. POM can only be supplied or administered 'in accordance with a prescription supplied by an appropriate practitioner'. Patient Group Directions allow supply or administration of a prescription only medicine by specified National Health Service bodies and specified individuals. They must be: written, signed by a doctor or dentist and a pharmacist, and signed by a representative of the specified body.