Mouth ulcers (canker sores) are small round or oval sores inside the mouth, for example on the inner cheeks, inner lips, tongue, or gums. The centre is whitish-yellow with a reddish edge. Although they are usually harmless and heal on their own within 1–2 weeks, mouth ulcers often sting and get in the way of eating, drinking, and talking.
What Are Mouth Ulcers?
In medical terms, mouth ulcers are called aphthous stomatitis or aphthous ulcers. They are different from sores caused by the herpes virus on the lips (cold sores): mouth ulcers appear inside the mouth and are not contagious. There are three commonly recognised types:
- Minor ulcers – the most common type, small (less than 1 cm) and heal within 7–14 days.
- Major ulcers – larger and deeper, can last more than 2 weeks and may leave a scar.
- Herpetiform ulcers – clusters of tiny sores that can merge into one larger sore.
Causes of Mouth Ulcers
The exact cause of mouth ulcers is not fully understood, but several factors are known to trigger them:
- Minor injuries in the mouth, such as biting your cheek, brushing too hard, rubbing from braces, or a sharp tooth.
- Stress and lack of sleep.
- Hormonal changes, for example before menstruation.
- Nutritional deficiencies such as iron, vitamin B12, folic acid, and zinc.
- Very acidic or spicy food, and toothpaste containing sodium lauryl sulfate (SLS) in some people.
- Certain health conditions, such as immune or digestive disorders, especially when ulcers keep coming back.
How to Treat Mouth Ulcers
Most mouth ulcers can be managed at home with the following steps:
- Keep your mouth clean. Brush your teeth twice a day with a soft-bristled toothbrush. An antiseptic mouthwash with chlorhexidine gluconate can help keep the sore clean from germs.
- Rinse with warm salt water several times a day to help ease discomfort.
- Use an oral gel for mouth ulcers applied directly to the sore, according to the directions for use.
- Temporarily avoid spicy, acidic, hot, or hard foods that can make the sore sting more.
- Get enough fluids and nutrients by drinking water and eating fruit and vegetables.
- Over-the-counter pain relievers can be used if needed, according to the directions.
The Minosep mouthwash range, such as MINOSEP Mild and MINOSEP Red, as well as MINOSEP Mouth Gel, contains chlorhexidine gluconate to help relieve mouth ulcers and protect the mouth from germs. Use as directed, because long-term use of chlorhexidine can cause tooth staining or a temporary change in taste.
Tips to Prevent Mouth Ulcers
- Use a soft-bristled toothbrush and brush gently.
- Chew slowly so you do not bite your cheek or tongue.
- Manage stress and try to get enough sleep.
- Eat a balanced diet rich in iron, vitamin B12, and folic acid.
- If you wear braces, cover sharp parts with orthodontic wax and keep the area around the brackets clean.
- Have your teeth checked by a dentist every 6 months.
When Should You See a Doctor or Dentist?
Get checked promptly if a mouth ulcer comes with any of the following:
- It has not healed after 2 weeks.
- It is large, very painful, or the number of sores keeps increasing.
- It keeps coming back, for example several times a month.
- It comes with fever, weakness, or difficulty eating and drinking.
- The sore is not painful but does not go away.
Conclusion
Mouth ulcers are usually mild and heal on their own. Keeping your mouth clean, avoiding triggers, and meeting your nutritional needs are key to speeding up recovery and preventing ulcers from coming back.
This article is for general information only and does not replace consultation, diagnosis, or treatment by a doctor or dentist. Use products according to the directions on the packaging.