soapberry, common name for the plant family Sapindaceae, a primarily tropical family of trees, shrubs, lianas, and herbaceous climbers, as well as a genus, Sapindus, in that family found in Asia and the Americas. The soapberry family includes the litchi. It also includes guaraná ( Paullinia cupana var. sorbilis ), an Amazonian shrub or liana cultivated for so long it is unknown in the wild. Regarded as an aphrodisiac, the seeds are very high in caffeine and are powdered and made into soft drinks or a tealike beverage or sold as pills or other medicinal preparations for a growing international market. The soapberry is classified in the division Magnoliophyta, class Magnoliopsida, order Sapindales.