The Nobel Prize in Physiology or Medicine 1982.
"for their discoveries concerning prostaglandins and related biologically active substances"
Sune K. Bergström (1916-2004), Bengt I. Samuelsson (1934-), and John R. Vane (1927-2004) received the Nobel Prize for discovering prostaglandins and working out their structure. In additon, Vane discovered the role of aspirin in inhibiting prostaglandin synthesis.
Prostaglandins are homones that mediate pain, inflamation and swelling. They also control blood clotting and and arterial constriction. See Why You need Linoleate and tomorrow's articles ("Prostaglandin Synthesis", "How Painkillers Work") for more information.