In the 2001 bioterrorist attack in the United States, in which at least 22 cases of anthrax occurred, there was initial uncertainty as to whether the index case was acquired from natural sources, and many of the additional cases posed diagnostic challenges to clinicians unfamiliar with the disease. The existence in Europe of terrorist groups with demonstrated violent tendencies suggests Europe is not immune to bioterrorist attack, and the same epidemiological and clinical confusion could happen here. Bacillus anthracis is distributed widely in the soils of Europe and foci of animal disease occur, notably in southern and eastern Europe. Sporadic human cases occur in these areas, and occasional additional cases have been acquired from contaminated, imported materials or acquired in countries outside of Europe, where anthrax may be common. Depending upon the intent of a bioterrorist, illness-caused B. anthracis could take one of several clinical forms-inhalational, cutaneous or gastrointestinal-and each would pose diagnostic difficulties. Understanding the epidemiologic, pathophysiologic and bioterrorism principles of anthrax are the clinician's best means of early detection of cases.