procarbazine: an antineoplastic drug used to treat Hodgkin's disease
antineoplastic: any of several drugs that control or kill neoplastic cells; used in chemotherapy to kill cancer cells; all have unpleasant side effects that may include nausea and vomiting and hair loss and suppression of bone marrow function
canada thistle: European thistle naturalized in United States and Canada where it is a pernicious weed