Diphtheria is a febrile, infectious disease caused by a bacterium: Klebs-Löffler bacillus, or Corynebacterium diphtheriae, which produces toxins that destroy the cells of the body. It is marked by fever and the development of a false membrane or pathological lining which covers the throat mucous membrane, causing suffocation when it spreads to the larynx. It also affects the nose, the skin, and heart. If left untreated, diphtheria can be fatal. Treatment consists in the administration of antitoxins and antibiotics, such as penicillin and erythromicin.