Catharanthus roseus, the Madagascar periwinkle or rosy periwinkle, is an attractive small subshrub with graceful pink or white salverform flowers. Native to southeastern and eastern Madagascar, the plant is easily cultivated, and European colonists exported it widely as an ornamental. It is now grown almost worldwide, and is found naturalized in most tropical and subtropical regions following escapes from cultivation. Madagascar periwinkle was used in Madagascar, and in many of the countries to which it was later spread, as a folk treatment for diabetes. Researchers investigating its medicinal properties discovered that it contained a group of alkaloids that, though extremely toxic, had potential uses in cancer treatment. Two of these alkaloids, vincristine and vinblastine, can be used in purified form to treat common types of leukemia and lymphoma. The discovery of vincristine is credited with raising the survival rate of childhood leukemia from under 10% to over 90%. Thousands of children’s lives have therefore been saved by an extract of this humble garden plant.