In antiquity, pharmacy and the practice of medicine were often combined, sometimes under the direction of priests, both men and women, who ministered to the sick with religious rites as well. Many peoples of the world continue the close association of drugs, medicine, and religion or faith. Specialization first occurred in the 8th century in the civilized world around Baghdad. It gradually spread to Europe as alchemy, eventually evolving into chemistry as physicians began to abandon beliefs that were not demonstrable in the physical world. Physicians often both prepared and prescribed medicines; individual pharmacists not only compounded prescriptions but manufactured medicaments in bulk lots for general sale.

 The modern pharmacist deals with complex pharmaceutical remedies far different from the elixirs, spirits, and powders described in the Pharmacopeia of London (1618) and the Pharmacopeia of Paris (1639). In the United States today, major medicines, those regarded as having the greatest therapeutic value, are selected for inclusion in the Pharmacopeia of the United States, first published in 1820. Selections for this resource are made by a Committee on Revision, whose members include the United States surgeon general and representatives of all colleges of medicine and pharmacy and all state medical and pharmaceutical associations