Around the 5th century BC, the Greek doctor Hippocrates (c. 460–c. 377 BC) described a miraculous powder that dulled muscle and joint pain, cured headaches, and reduced fever. Hundreds of years later, scientists discovered that this bitter substance, which in Hippocrates’ time was extracted from willow tree bark, contained a compound now known as salicin, which the body converts into salicylic acid. This chemical, in turn, was the basis for modern-day aspirin, a medication that one of its manufacturers has called “the wonder drug that works wonders.”

Salicylic acid in its purest form was indeed an effective pain reliever and fever reducer, but it also upset stomachs and led to bleeding in the digestive tract. In the late 1800s, the German scientist Felix Hoffman (1868–1946) set out to find a new compound that would help his father’s arthritis without causing stomach distress. Working for the Bayer company, Hoffman created acetylsalicylic acid (ASA)—a modified version of salicylic acid that worked just as well but was much gentler on the stomach. In 1899, the company began marketing the new drug as aspirin.

Today, Americans take about 80 billion aspirin tablets a year. The drug is used to relieve pain from headaches, menstrual cramps, colds, toothaches, and muscle aches, as well as symptoms of lupus and other rheumatologic conditions in which the immune system attacks part of the body. Because aspirin can help prevent blood clots from forming, many people who have suffered heart attacks or strokes now take a low-dose aspirin a day to prevent recurrence. Aspirin can also reduce fever, possibly by affecting the brain’s hypothalamus, which controls body temperature. The drug travels through the bloodstream to all parts of the body and is filtered out in the urine within 4 to 6 hours.

Aspirin works by binding to cyclooxygenase-2 (COX-2) enzymes, stopping them from producing chemicals called prostaglandins that play a role in pain, swelling, and blood clotting. COX-2 enzymes are often found in tissue that has been damaged by injury or sickness. But aspirin also inhibits a similar enzyme, COX-1, that helps protect the stomach lining; this is one reason why aspirin and its relatives can cause nausea and damage the digestive tract.

ADDITIONAL FACTS

  1. Aspirin comes in both prescription and nonprescription strengths and is available as plain tablets, enteric-coated tablets, delayed-release formulas, chewable tablets, gums, and rectal suppositories.
  2. People who have asthma, frequently stuffed or runny noses, or nasal growths called polyps are at higher risk for an allergic reaction to aspirin.
  3. In children, aspirin can cause a life-threatening condition called Reye’s syndrome, in which fat builds up in the brain, liver, and other organs.