cancer root
/ˈkansə ˌruːt/Chiefly North American
noun
Any of various plants used medicinally; especially any of several parasitic plants of the genera Orobanche and Conopholis (family Orobanchaceae), formerly used to treat skin complaints such as ulcers, and believed by some to be effective against cancer.
Origin
Early 18th century; earliest use found in Philosophical Transactions of the Royal Society of London. From cancer + root, probably so called either on account of its use in the treatment of ulcers and cancers or perhaps on account of the plants' parasitic nature.