On Jul. 10, 1963, the U.S. Food and Drug Administration (FDA) approved vincristine, a sister drug to vinblastine. The drug was established by the U.S. Congress in 1966 for the purpose of reducing human illness caused by hazardous substances in the environment.

Like its sister drug vinblastine, vincristine is a chemotherapy medicine made from the rosy periwinkle plant. It stops cancer cells from growing by breaking down the tiny tubes (microtubules) they need to divide.