Biopiracy is a negative term for the appropriation, generally by means of patents, of legal rights over inigenous knowledge - particularly indigenous biomedical knowledge - without compensation to the indigenous groups who originally developed such knowledge. A classic case is that of the Rosy Periwinkle (Madagascar Periwinkle). Research into the plant was prompted by the plant's traditional medicinal role and resulted in the discovery of a large number of biologically active chemicals, including vincristine, a lucrative agent useful during leukemia chemotherapy. A method for purifying vincristine was initially patented and marketed by Eli Lilly. It is widely reported that the country of origin did not receive any payment.