Crystalline caffeine-alkaloid, solid, white and bitter taste, addictive stimulant of the autonomous nervous system, maintains wakefulness, is extracted from coffee; when extracted from guarana is called guaranin, from the matte is called matein and tea, theine, but they are the same alkaloid; medicinally it is used against headache, bronchial asthma, gallbladder cramps and in cardiovascular diseases.