The Soursop is a flowering, evergreen tree native to tropical regions of the world. It also contains a long, prickly green fruit which may be effective against some forms of cancer.Annona muricata is an active principle in an herbal remedy marketed under the brand name Triamazon. According to Cancer Research UK, "in laboratory studies, graviola extracts can kill some types of liver and breast cancer cells that are resistant to particular chemotherapy drugs. But there haven't been any large scale studies in humans. So we don't know yet whether it can work as a cancer treatment or not."This tree is low and is called graviola in Brazil, guanabana in Spanish and has the uninspiring name "soursop" in English. The fruit is very large and the subacid sweet white pulp is eaten out of hand or, more commonly, used to make fruit drinks and sherbets.