"If You're a Viper" (originally released under the title "You'se a Viper", and sometimes titled "If You'se a Viper") is a jazz song composed by Stuff Smith. It was first recorded by Smith and his Onyx Club Boys in 1936 and released as the b-side to the song "After You've Gone". The song was a hit for Smith and is one of the most frequently covered songs about marijuana smoking in American popular music. In its early history the song was identified with Rosetta Howard's 1937 recording and sometimes still is. Howard slowed the song's tempo considerably, and rewrote significant portions of the vocal melody (for example, the line "bust your conk on peppermint candy"). Fats Waller, who recorded the song in 1943 for a V-Disc session, closely followed the Howard arrangement, and his version, which has been commercially released numerous times since the 1950s, has kept the song in circulation. Waller's track is also a small footnote in the story of Harry J. Anslinger's efforts to prosecute jazz musicians for smoking marijuana during World War II. (en)