Graviola, also called Soursop, is a small evergreen tree found in the warmest parts of the tropics, especially the Amazon. Through the years the indigenous people have used all parts of the graviola for medicinal purposes. Scientists began studying graviola in the 1940's and confirmed many of their uses. A number of active compounds and phytochemicals have been isolated in graviola. Research has shown graviola to have hypotensive (lowers blood pressure), antispasmodic, anti-bacterial and anti-fungal properties.