An ulcer (from Latin ulcus) is an open sore of the skin, eyes or mucous membrane, often caused by an initial abrasion and generally maintained by an inflammation and/or an infection.

Anthrax is an acute disease caused by Bacillus anthracis. It affects both humans and animals and most forms of the disease are highly lethal. There are effective vaccines against anthrax, and some forms of the disease respond well to antibiotic treatment.