- Physical Examination
- Surgical Examination
- Ophthalmology
- Clinical Skills
- Orthopedics
- Surgery Videos
- Laparoscopy
- Pediatrics
- Funny Videos
- Cardiothoracic Surgery
- Nursing Videos
- Plastic Surgery
- Otorhinolaryngology
- Histology and Histopathology
- Neurosurgery
- Dermatology
- Pediatric Surgery
- Urology
- Dentistry
- Oncology and Cancers
- Anatomy Videos
- Health and Fitness
- Radiology
- Anaesthesia
- Physical Therapy
- Pharmacology
- Interventional Radiology
- Cardiology
- Endocrinology
- Gynecology
- Emergency Medicine
- Psychiatry and Psychology
- Childbirth Videos
- General Medical Videos
- Nephrology
- Physiology
- Diet and Food Health
- Diabetes Mellitus
- Neurology
- Women Health
- Osteoporosis
- Gastroenterology
- Pulmonology
- Hematology
- Rheumatology
- Toxicology
- Nuclear Medicine
- Infectious Diseases
- Vascular Disease
- Reproductive Health
- Burns and Wound Healing
- Kidney Zone Podcast
- Other
Mouth ulcers
Category: Head, Eyes, Ears, Nose & Throat · All head & senses symptoms
What it can feel like
Mouth ulcers are painful, shallow sores inside the mouth — on the cheeks, lips, tongue or gums. Small round ulcers that heal within one to two weeks (aphthous ulcers) are common and usually harmless; the exceptions are ulcers that do not heal, which always need examining.
Possible causes
A symptom can have many causes, and most are not serious. The lists below group conditions this symptom can be associated with — common causes first. They are possibilities to discuss with a clinician, not a diagnosis.
Common causes
Mouth ulcers can be associated with minor trauma (biting, hard food, dental appliances), stress, tiredness, hormonal changes, and deficiencies of iron, vitamin B12 or folate in people who get them recurrently.
Other possible causes
Ulcers that fail to heal within about three weeks can be associated with oral cancer and must be examined. Recurrent widespread ulcers can accompany inflammatory bowel disease, Behçet's pattern, or immune problems.
Red flags — when to seek help promptly
- An ulcer that has not healed within three weeks
- An ulcer with a hard lump, bleeding or numbness of the lip or tongue
- Ulcers with genital ulcers, eye inflammation or joint pains
- Many large, frequent ulcers with weight loss or bowel symptoms
What a clinician may do
A clinician or dentist will examine the ulcer and the rest of the mouth, ask about frequency and trauma, and arrange blood tests for iron and vitamins if ulcers recur. Non-healing ulcers are referred urgently for biopsy.
Watch: related videos
Examination and clinical videos from the MedicalVideos.com library relevant to this symptom. Some clinical footage is graphic — that is the nature of a medical video library.
Related guides on MedicalVideos.com
Frequently asked questions
Why three weeks for an ulcer but days for most things?
Because ordinary mouth ulcers heal in seven to fourteen days, a three-week ulcer has declared itself different. Oral cancers caught at the ulcer stage are far more curable, so dentists and doctors treat non-healing as the trigger for urgent referral.
Can toothpaste cause mouth ulcers?
In some people, yes — the detergent sodium lauryl sulphate in many toothpastes is associated with more frequent aphthous ulcers. A trial of an SLS-free toothpaste is a reasonable step for recurrent ulcers, alongside checking iron and B12.
Related symptoms — Head, Eyes, Ears, Nose & Throat
Browse the M section of the A–Z list or return to the Symptoms A–Z hub.