药物(drug)
指能够影响生物功能的化学物质，可供治疗、诊断和预防疾病用。常用药包括有抗生素、兴奋剂、安定剂、抗抑郁药、镇痛药、麻醉性镇痛药、荷尔蒙和各种特定用途药，如轻泻药、强心剂、抗凝血药、利尿剂和抗组织胺药。疫苗有时也被视为一种药物。医学药物的作用有︰可保护以对抗入侵的有机体（或杀死它们、或中止其复制，或阻断其对宿主的影响）；补充体内缺少的物质或将之排出体外；干扰一项不正常的程序。药物的使用法有口服、肛门塞剂、皮下注射、肌肉注射、静脉注射和吸入等。已知最古老的药典是西元前1700年古巴比伦尼亚的一块石碑；1928年抗生素的发明象徵了现代药物时代的来临。今日，多数药物是由化学法合成，也有许多重要药物（如许多抗生素和疫苗）是由植物、动物、矿物和微生物中萃取纯化而得。使用药物不止要其反应也要安全；副作用的程度可从轻微到危险（参阅medicinal poisoning）。许多违禁药物也可以用於医学上（参阅cocaine、heroin和drug addiction）。亦请参阅drug resistance、pharmacology、pharmacy。
English version：
drug
Any chemical agent that affects the function of living things. Some, including antibiotics, stimulants, tranquilizers, antidepressants, analgesics, narcotics, and hormones, have generalized effects. Others, including laxatives, heart stimulants, anticoagulants, diuretics, and antihistamines, act on specific systems. Vaccines are sometimes considered drugs. Medicinal drugs may protect against attacking organisms (by killing them, stopping them from reproducing, or blocking their effects on the host), substitute for a missing or defective substance in the body, or interrupt an abnormal process. A drug must bind with receptors in or on cells and cannot work if the receptors are absent or its configuration does not fit theirs. Drugs may be given by mouth, by injection, by inhalation, rectally, or through the skin. The oldest existing catalogue of drugs is a stone tablet from ancient Babylonia (c. 1700 BC); the modern drug era began when antibiotics were discovered in 1928. Synthetic versions of natural drugs led to design of drugs based on chemical structure. Drugs must be not only effective but safe; side effects can range from minor to dangerous (see medicinal poisoning). Many illegal drugs also have medical uses (see cocaine, heroin, drug addiction). See also drug resistance, pharmacology, pharmacy.
