What are the reasons for mouth ulser?

Mostly unknown: Most often related to a viral process, the cause unknown. Most are apthous ulcers. They come and go and may be related to stress.

Many reasons : Stress, nuts, chocolate, citrus food are few factors.

Canker sores: Canker sores are the most common oral lesions. The cause is unknown. Topical medications otc applied directly, mouthwashes, and oral medications can relieve pain or inflammation. Rec.: if not comfortable see a dentist for soft tissue laser treatment.