there are so many causes of mouth ulcers like-
-Stress or tissue injury is thought to be the cause of simple mouth ulcers.
-Certain foods, including citrus or acidic fruits and vegetables (such as lemons, oranges, pineapples, apples, figs, tomatoes and strawberries), can trigger a mouth ulcer.
-Sometimes a sharp tooth surface also trigger mouth ulcers.
-Some cases of complex mouth ulcers are caused by an underlying health condition, such as an impaired immune system; nutritional problems, such as vitamin B-12, zinc, folic acid, or iron deficiency and gastrointestinal tract disease, such as Coeliac disease and Crohn's disease.
-When you first quit smoking, you may develop more mouth ulcers than normal, but this is temporary.
Usually ulcer heals by itself only within 1 week.
You can take 'Becosule capsule' once in a day for 1 week for faster recovery.
Temporarily you can apply mucopain gel over ulcer for relief..