The intestinal disease form of anthrax may follow the consumption of contaminated food and is characterized by an acute inflammation of the intestinal tract. Initial signs of nausea, loss of appetite, vomiting, and fever are followed by abdominal pain, vomiting of blood, and severe diarrhea.

Direct person-to-person spread of anthrax is extremely unlikely, if it occurs at all. Therefore, there is no need to immunize or treat contacts of persons ill with anthrax, such as household contacts, friends, or coworkers, unless they also were also exposed to the same source of infection.

In persons exposed to anthrax, infection can be prevented with antibiotic treatment.

However, bioterrorists may "weaponize" or mutate anthrax to be resistant to known antibiotics (antibiotics are drugs that kill bacteria). It is because of this weaponization that it is critical to have a steady stream of new drugs and targets in the pipeline. During weaponization, the known antibiotic is actually used to "evolve" anthrax and strains are selected that are resistant to the antibiotic. During the Gulf War, the U.S. Government had troups carry Cipro because it was the newest antibiotic available and the Iraqis would not have had time to weaponize anthrax against it. For the latest public terrorist attack, Cipro was again chosen, but in this case the anthrax strains used might have already been weaponized to resist Cipro.

Early antibiotic treatment of anthrax is essential–delay lessens chances for survival. Anthrax usually is susceptible to penicillin, doxycycline, and fluoroquinolones.

An anthrax vaccine also can prevent infection. Vaccination against anthrax is not recommended for the general public to prevent disease and is not available.