Hua Tuo (華佗, ca. AD 145-220) was a Chinese surgeon of the 2nd century AD. According to the "Records of Three Kingdoms" (ca. AD 270) and the "Book of the Later Han" (ca. AD 430), Hua Tuo performed surgery under general anesthesia using a formula he had developed by mixing wine with a mixture of herbal extracts he called "mafeisan" (麻沸散). Hua Tuo reportedly used mafeisan to perform even major operations such as resection of gangrenous intestines. Before the surgery, he administered an oral anesthetic potion, probably dissolved in wine, in order to induce a state of unconsciousness and partial neuromuscular blockade.