A condition of the mouth that involves swelling called inflammation and open sores called ulcers.

Stomatitis has various causes. These include infections with certain viruses, germs and fungi. Other causes include allergens, mouth injuries, tobacco, irritating foods or chemicals, chemotherapy, radiation, and conditions such as Celiac disease and inflammatory bowel disease.

Stomatitis symptoms can affect the lips and the lining inside the mouth. Symptoms include swelling, changes in tissue color, and one or more painful ulcers. The inside of the mouth may feel like it's burning. Some people may have a fever. The symptoms can lead to trouble eating, dehydration and lack of nutrition.

With stomatitis, the underlying cause of the condition is treated. Medicines placed on the lips or inside the mouth are used to relieve symptoms. A soft toothbrush and saltwater rinse may help prevent new or other infections. A soft diet with no salty or acidic foods can make it easier to eat and drink.