[The history of biological warfare]

Selected events in the history of biological weapons are highlighted to increase the physician's awareness of this crucial threat. The deliberate use of biological substances originated in antiquity and has pervaded the history of human wars throughout time until the 21th century. The history of biological warfare is difficult to assess because of a number of confounding factors. These include the difficulty in verification of allegation, the use of the threat of this weapon for propaganda purposes, the lack of microbiological or epidemiological data, and the incidence of natural occurring endemic or epidemic diseases during hostilities. Although it may be problematic to verify at times, the use of such weapons has not been limited to national armies or militia. Frustrated civilians, terrorists and even physicians have used biological substances to promote their interests. Today, the biological threat has become more serious. It's potency, cost-effectiveness, and the ability to manufacture and deploy it with little sophistication, or under the semblance of legitimate commercial endeavors, will ensure that biological weapons remain a constant threat to human health.