People take aspirin somewhere between 50 and 120 billion times a year, yet for most of its commercial life no one knew how it worked. This episode traces it from willow bark and meadowsweet, recorded on Sumerian clay tablets and in the Ebers Papyrus and prescribed as a tea by Hippocrates, to the Reverend Edward Stone, who in 1763 tasted bitter willow bark, dried it for feverish parishioners, and reported to the Royal Society. Charles Gerhardt first synthesized acetylsalicylic acid in 1853, and in 1897 Bayer produced a stable, more tolerable form, with credit disputed between Felix Hoffmann and Arthur Eichengrün.

Bayer launched the name Aspirin in 1899, then lost the trademark in the United States and other countries after World War I. In 1971 John Vane showed that aspirin blocks prostaglandins and thromboxanes, work that earned the 1982 Nobel Prize. It does so by permanently disabling the COX enzyme, a process called suicide inhibition, which matters because platelets have no nucleus and cannot replace it. The episode covers Reye’s syndrome, why chronic overdose carries a 25 percent mortality rate against about 2 percent for acute overdose, the 2022 task force reversal, and a March 2025 Nature study on cancer.

• How the name combines acetyl, Spirsäure from meadowsweet, and a standard drug suffix
• Why Canadian generics must be sold as ASA instead of aspirin
• The vinegar smell that signals aspirin breaking down through hydrolysis
• How salicylate swings blood chemistry from respiratory alkalosis to metabolic acidosis
• Hijacked platelets using thromboxane A2 to hide metastasizing cancer cells from T cells