Pawpaw is toxic to some cancer cells, but such effects have not been shown in humans.
The plant extract is used in anti-lice shampoo and in pesticides.
In lab studies, the extract killed cancer cells resistant to commonly used chemotherapy drugs such as adriamycin.
It also appeared to be more toxic to cancer cells than to normal cells.
However, studies on these effects have not been conducted in humans.
Cancer treatment Test tube studies suggest pawpaw may have activity against cancer cells, but experiments in mice produced conflicting results.
There are no published clinical studies in humans that test safety or effectiveness of pawpaw as a cancer treatment.
Pawpaw should not be confused with graviola, also known as Brazilian pawpaw, or with papaya, another fruit with a similar texture and appearance.
In vitro studies show that pawpaw extract has cytotoxic effects against cancer cell lines including those resistant to adriamycin.
Clinical studies have not been conducted.