The purpose of this series of articles is to present to health personnel an updated summary on bioterrorism associated agents. In this first article an updated summary on anthrax is presented. Emphasis has been placed on the characteristics of cases which occurred during October in the United States of America and on the experience of governmental agencies of that country to face the emergency. Measures implemented in Mexico are described as well. The authors are convinced that the best arm against terror is timely and updated information.