Aspirin

Irritated or stimulated blood cells secrete arachidonic acid (a slippery substance that makes cells flexible), which in turn produce one particular prostaglandin (a group of hormone-like fatty acids) that causes inflammation and fever: “Think of a line of dominoes falling one on to another . . . When cells are disturbed, they produce arachidonic acid. This leads to the formation of prostaglandins, which in their turn create fever or inflammation, and most like (Vane reasoned) pain too. Then think of something coming between the first two dominoes and the others, preventing them from knocking over their fellows. That’s what aspirin did. By stopping prostaglandins being made, it halted the resulting fever, inflammation and pain. John Vane had figured out how aspirin worked” (Jeffreys, 230).