Stomatitis is an inflammation of the mucous membranes in the mouth, which can cause pain, swelling, and sores. It can affect various parts of the mouth, including the cheeks, gums, tongue, and lips. Common causes include infections, irritants, allergies, and certain medical conditions. Symptoms of stomatitis may include mouth sores, difficulty eating or swallowing, and a burning sensation. Treatment typically focuses on relieving symptoms and addressing the underlying cause, which may involve medications, mouth rinses, or dietary changes. Maintaining good oral hygiene is also important in managing this condition.