Inflammation of the mucous membrane of the mouth. There are various causes, one of which is infection from the fungus Candida albicans, causing creamy-white patches throughout the mouth, or redness and inflammation of the oral mucous membrane. The condition is also known as oral thrush. The herpes simplex virus, among others, can also cause inflammation of the mouth; the virus, which is also responsible for cold sores, causes small blisters throughout the oral cavity. Inflammation of the mouth can be a secondary result of another condition, such as certain blood or serious skin disorders, but also of smoking. Candida infection can also be related to other disorders such as diabetes mellitus or cancer. Oral inflammation with the formation of ulcers can occur without a particular cause, in which case it is known as stomatitis aphthosa. The condition may consist of one or more ulcers, without general oral inflammation; it is very-painful and difficult to treat. Treatment is always according to the cause. With viral infections only the symptoms can be treated (with painkillers, a liquid diet and mouth washes). Candida fungus is susceptible to nystatin. Hydrogen peroxyde is also effective. A general disorder should be treated separately.