[防毒, fáng dú, ㄈㄤˊ ㄉㄨˊ]defense against poison; defense against poison gas; anti-narcotics measures; defense against computer viruses#41020[Add to Longdo]
[以毒攻毒, yǐ dú gōng dú, ㄧˇ ㄉㄨˊ ㄍㄨㄥ ㄉㄨˊ]to cure ills with poison (成语 saw, refers to technique of traditional Chinese medicine); to fight evil with evil; set a thief to catch a thief; to fight fire with fire#60994[Add to Longdo]