以毒攻毒 [ㄧˇ ㄉㄨˊ ㄍㄨㄥ ㄉㄨˊ; yi3 du2 gong1 du2] to cure ills with poison (idiom, refers to technique of traditional Chinese medicine); to fight evil with evil set a thief to catch a thief to fight fire with fire ◄ ►