OBJECTIVE: To develop consensus-based recommendations for measures to be taken by medical and public health professionals following the use of anthrax as a biological weapon against a civilian population. PARTICIPANTS: The working group included 21 representatives from staff of major academic medical centers and research, government, military, public health, and emergency management institutions and agencies. EVIDENCE: MEDLINE databases were searched from January 1966 to April 1998, using the Medical Subject Headings anthrax, Bacillus anthracis, biological weapon, biological terrorism, biological warfare, and biowarfare. Review of references identified by this search led to identification of relevant references published prior to 1966. In addition, participants identified other unpublished references and sources. CONSENSUS PROCESS: The first draft of the consensus statement was a synthesis of information obtained in the formal evidence-gathering process. Members of the working group provided formal written comments which were incorporated into the second draft of the statement. The working group reviewed the second draft on June 12, 1998. No significant disagreements existed and comments were incorporated into a third draft. The fourth and final statement incorporates all relevant evidence obtained by the literature search in conjunction with final consensus recommendations supported by all working group members. CONCLUSIONS: Specific consensus recommendations are made regarding the diagnosis of anthrax, indications for vaccination, therapy for those exposed, postexposure prophylaxis, decontamination of the environment, and additional research needs.