Graviola tree fruit extract, also called "sour sop juice," is an herbal remedy sometimes advertised as being a potent anticancer agent. As of 2014, very little medical evidence exists to substantiate these claims.
Graviola is an evergreen tree native to Mexico, Central America, the Caribbean and the northern part of South America. It is more commonly called "soursop" in English. It produces a palatable fruit that is widely used in fruit drinks and confections in its native regions.
Some marketers of herbal supplements have claimed that the fruit itself or a fruit extract is a potent killer of cancer cells. While there is some medical evidence that some of the chemicals present in graviola increase the longevity and effectiveness of anticancer drugs, there is no evidence at present that indicates the fruit or its extract has this effect. As of 2014, Cancer Research U.K.reports that no cancer organizations that they consider reputable support the use of graviola as a treatment.
In the United States, herbal and natural supplements are only very minimally regulated by the Food and Drug Administration, so marketers have some leeway to make grandiose claims that are not properly supported by medical studies and clinical trials. While graviola may turn out to be beneficial as a part of a cancer treatment regimen, claims that it "kills cancer" are not supported by evidence.