Botox is a brand name for a purified form of botulinum toxin used medically and cosmetically, most famously to relax facial muscles and temporarily reduce wrinkles. Injected in tiny doses, it works by blocking nerve signals to targeted muscles, with effects lasting several months. Beyond cosmetics, it treats migraines, muscle spasms and excessive sweating. The word is widely used as shorthand for cosmetic injections in popular culture.