Caffeine (also spelled caffein) is a bitter, white crystalline xanthine alkaloid that is a psychoactive stimulant. Caffeine was isolated from coffee in 1820 by a German chemist, [Friedlieb Ferdinand Runge [1], and in 1821 by French chemists working independently; viz., by Pierre Jean Robiquet [2], and by Pierre Joseph Pelletier [3] and Joseph Bienaimé Caventou [4]. It was Pelletier, noting that the drug had been isolated from coffee (French: café), who coined the word "cafeine", which became the English word "caffeine". File:200px-Caffeine-3D-vdW.png