The recent occurrence in the USA of deliberate release of virulent Bacillus anthracis in letters sent to three media corporations and to the American senate has led to a great anxiety in Sweden and elsewhere in Europe. Numerous letters have been suspected to contain B. anthracis spores and several have contained powder of different types. In none of the tested letters collected by the Swedish police have we been able to detect anthrax bacilli. Powder containing letters have been tested with either bacterial isolation and/or B. anthracis specific PCR. Anthrax is a disease found naturally in herbivores and is occasionally spread to humans. It is caused by the gram-positive rod B. anthracis that was discovered by Robert Koch in 1876. Beginning in the 1930s many states have developed B. anthracis for use as a weapon. A few releases of the bacteria have been reported before October 2001. B. anthracis causes three forms of disease, cutaneous, pulmonary and gastro-intestinal. The pulmonary form is the most dangerous and may lead to death merely one to two days after onset of severe symptoms. This is due to the rapid growth and release of several potent toxins that engage the immune system and promote tissue destruction. B. anthracis infection can be treated with several antibiotics, among which quinolones and tetracyclins have been recommended. Diagnosis can readily be achieved by microscopy, bacterial isolation and PCR at the Swedish Institute for Infectious Disease Control and the Swedish Defence Research Agency. Antibiotics relevant for treatment of B. anthracis infections are already stockpilled in our country. Further actions to strengthen our capability to deal with bioterrorism are ongoing.