乌头碱（Aconitine）是常用中药乌头中所含有的一种化学物质，具强烈毒性，口服0.2mg左右即能使人中毒，3—5mg即可致死。民间常用草乌、川乌等植物来泡制药酒。

本品具有镇痛作用，临床上用于缓解癌痛，尤其适用于消化系统癌痛；外用时能麻痹周围神经末梢，产生局部麻醉和镇痛作用；有消炎作用，本品毒性极大，能兴奋麻痹感觉神经和中枢神经，兴奋心脏迷走神经，直接毒害心肌细胞。还有发汗作用。

Aconitine is a toxin produced by the Aconitum plant, also known as devil’s helmet or monkshood. Monkshood is notorious for its toxic properties. In China, aconitine is also used in small doses as an analgesic.