Guarana is an extract of roasted and pulverized seeds of the plant Paullinia cupana which is indigenous to the Amazon Basin and whose major active components are caffeine and other xanthine alkaloids such as theophylline and theobromine. Guarana has been used as a stimulant and tonic to treat fatigue, decrease hunger and thirst and for headaches and dysmenorrhea. In conventional doses, guarana has few side effects and has not been linked to episodes of liver injury or jaundice.