The essential oil from guarana [Paullinia cupana H.B.K. var. sorbilis (Mart.) Ducke] was analysed. Nine components were identified, namely (2) methylbenzenes, (1) cyclic monoterpene and (2) cyclic sesquiterpene hydrocarbons, (2) methoxyphenylpropenes and (2) alkylphenol derivatives. The alleged psychoactivity of the essential oil is presumably due to the identified constituents estragole and anethole. Any contribution of aminated metabolites of estragole/anethole to the alleged psychoactivity of the essential oil of guarana can be excluded. Neither the psychoactive 4-methoxyamphetamine nor tert-aminoketones could be traced in human urine after oral application of guarana.