Pharmacology is that part of medicine specifically concerned with how drugs (i.e. chemicals both naturally occurring and manufactured) affect the body’s biochemical functioning. Those chemicals that can be used for medicinal purposes – that is to say, to diagnose, treat or prevent disease – are therefore called pharmaceuticals. The ideas behind modern, scientific pharmacology only emerged in a meaningful way in the 19th century.
Humankind’s attempts to cure illness by the application of natural plant-based substances have a prehistoric heritage, while the first documented use of medicinal drugs is contained in the Egyptian Kahun Papyri, dating to around 1800 BCE. Among the treatments detailed in these documents was the taking of honey to fight infection. Then, from about 1500 BCE, the Babylonians are known to have produced pills and creams for medical use.
The medieval age saw the publication of several important overviews of medicinal knowledge – notably the 9th-century Arabic tome De Gradibus, in which Al-Kindi strove to quantify the strength of various drugs, and Avicenna’s 11th-century epic The Canon of Medicine. Nonetheless, pharmacology was very basic – opium and quinine were among the most effective drugs available but the widespread use of metal-based compounds was often actively injurious to the patient. Nor would things improve much until the early decades of the 1800s, when figures such as French physiologists François Magendie and Claude Bernard pioneered the scientific study of the physiological effects of specific drugs through a process of experimentation and observation. They built upon the legacy of William Withering (1741–99), who had identified digitalis as the active ingredient in a folkloric herbal remedy for dropsy. Then, in 1847, the German Rudolf Buchheim became the university professor of pharmacology at Dorpat (in what is now Estonia), bringing an unprecedented level of scientific rigour to the study of drugs and their effects. He is credited with changing pharmacology from an essentially descriptive discipline to an experimental one.
Come the 20th century, and pharmacology was firmly established not only as an academic discipline but as a major new industry and pharmaceutical laboratories became the focus of medical practice.