化学战(chemical warfare)
在战争中使用化合物（一般为毒剂）或化学剂之类的方法战斗。化合物包含致命性或非致命性化学剂。这些战剂用在人类身上会麻痹神经系统（如神经毒气、沙林毒气和VX毒气），可短暂致盲、致聋、致瘫，引起恶心、呕吐、窒息，或严重灼伤皮肤、眼睛或肺部。还包括为达到军事目的所使用的化学落叶剂、除莠剂，如药剂橙。化学战在第一次世界大战中首次大量应用。1915～1918年德军发明一系列毒气如氯气、光气和芥子气。协约国立即仿效，同时改进防毒面具以保护士兵。交战最後一年双方均大量使用芥子气。由於世人普遍的反对导致1925年世界各国在日内瓦签署协定禁止化学战，是故在第二次世界大战中参战国一般都能克制，虽然当时德国人还研制成功了神经性毒气，义大利和日本人则曾用毒气对付一些敌人。1980年代两伊战争中伊拉克和伊朗双方都有使用化学武器，1991年波斯湾战争时，伊拉克也曾威胁要使用化学武器。参阅biological warfare。
English version：
chemical warfare
Use of chemical compounds, usually toxic agents, in warfare, and the methods of combating such agents. The compounds involved may be lethal or nonlethal. In humans, they generally paralyze the nervous system (nerve gases, such as sarin and VX); induce temporary blindness, deafness, nausea, or vomiting; cause severe burns to skin, eyes, or lungs; or stifle respiration. Also included are chemical defoliants and herbicides used for military purposes, such as Agent Orange. World War I saw the first significant use of chemical warfare. From 1915 to 1918 the Germans introduced—and the Allies duplicated—a succession of poison gases: chlorine, phosgene, and mustard gas. The Allies also developed gas masks to protect soldiers. In the war's final year both sides used mustard gas extensively. Universal revulsion led to a 1925 Geneva protocol banning chemical warfare, which generally held through World War II, though the Germans developed highly toxic nerve gases and both Italy and Japan used gas against some of their enemies. Both Iran and Iraq used chemical weapons in the Iran-Iraq War in the 1980s, and Iraq threatened to use them in the Persian Gulf War in 1991. See also biological warfare.