什麼是毒物

任何會損害活組織、致傷或致死的物質（自然物或合成物）。由活的生物機體自然產生的毒物通常被稱爲毒素，若由動物產生則稱爲動物毒液。毒物可能是被嚥下、吸入或由皮膚吸收。毒物不一定具有全或無效應；一些毒物的毒性比另一些毒物要大得多，如0.25克氰化鉀就足以致命，而一次服用大量的精製食鹽也會致命。毒性可以是急性的（攝入一劑之後立刻出現症狀）或者慢性的（反覆或持續攝入毒物後最終出現症狀，攝入化學性的致癌物質就是這樣）。中毒反應可以是局部的（麻疹、水泡、發炎）或全身的（全身出血、抽搐、嘔吐、腹瀉、感覺模糊、麻痹、呼吸或心跳停止）。農業上的殺蟲劑通常對人類是有毒的。一些工業用化學品具有高度毒性或是致癌物質。大多數藥劑和保健品在不恰當服用或超量服用情況下都是毒物。大多數形式的放射線也是有毒的（參閱radiation injury）。亦請參閱antidote、arsenic poisoning、fish poisoning、food poisoning、lead poisoning、medicinal poisoning、mercury poisoning、mushroom poisoning。

poison

Any substance (natural or synthetic) that damages living tissues and injures or kills. Poisons spontaneously produced by living organisms are often called toxins, or venoms if produced by animals. Poisons may be ingested, inhaled, injected, or absorbed through the skin. They do not always have an all-or-none effect; some are far more toxic than others (e.g., 0.25 g of potassium cyanide may kill, whereas a massive single dose of table salt can kill). Poisoning may be acute (a single dose does significant damage) or chronic (repeated or continuous doses produce an eventual effect, as with chemical carcinogens). The effects produced by poisons may be local (hives, blisters, inflammation) or systemic (hemorrhage, convulsions, vomiting, diarrhea, clouding of the senses, paralysis, respiratory or cardiac arrest). Agricultural pesticides are often poisonous to humans. Some industrial chemicals can be very toxic or carcinogenic. Most drugs and health-care products can be poisons if taken inappropriately or in excess. Most forms of radiation can be toxic (see radiation injury). See also antidote, arsenic poisoning, fish poisoning, food poisoning, lead poisoning, medicinal poisoning, mercury poisoning, mushroom poisoning.