Pharmacology is the branch of medicine and biology concerned with the study of drug action. A drug is any chemical substance that affects the function of a living organism. Drugs may be used to treat disease, relieve symptoms, or alter mental states. The study of pharmacology encompasses all aspects of the interaction between drugs and living organisms, including the mechanisms by which drugs are absorbed, distributed, metabolized, and excreted. It also includes the study of how drugs interact with each other and with their target tissues or cells.
The word pharmacology comes from two Greek words: pharmakon, meaning “drug”, and logos, meaning “study”. The term was first used in print by German physician Johann von Goethe in his book Die Wahlverwandtschaften (Elective Affinities), published in 1809. The book is about a man who falls in love with a woman who is already married to someone else. In one scene, the man gives her a poisonous plant as a gift; she eats it and dies. In another scene, he gives her a potion that makes her fall asleep; she wakes up later to find that he has died.
The science of pharmacology has its roots in antiquity. The earliest known reference to medicinal plants is found in a Sumerian tablet dating back to 3100 BC. The Ebers Papyrus, an Egyptian medical text dating back to 1550 BC, contains descriptions of over 800 different medicines made from plants, animals, and minerals. Hippocrates (460-377 BC), considered the father of medicine, described more than 400 different drugs made from plants in his work De Materia Medica. Galen (129-200 AD), a Roman physician who wrote extensively on pharmacology and physiology, identified dozens of active ingredients in various medicinal plants and preparations.
Throughout history people have used substances found in nature for their medicinal properties without really understanding how they work or what effect they will have on the body. Many ancient cultures believed that diseases were caused by evil spirits or imbalances in the body’s humors (bloods