Mouth ulcers are small painful sores that can develop anywhere in the lining of the mouth. They form when part of the sensitive tissue (mucous membrane) of the mouth is eroded, exposing the nerves that lie beneath.


The most common cause of mouth ulcers is injury to the mouth, such as biting your cheek. They can also develop as a result of infectious diseases such as herpes or thrush, poor dental hygiene, stress and taking certain medications. In most cases, mouth ulcers are harmless and clear up by themselves after a few days without the need for medical treatment. Aphthous ulcers are recurring ulcers with no known cause that affect around 20% of the Australian population. Seek medical treatment/advice if your ulcers don’t clear up within a few days, or you’re troubled by frequent ulcers.



The symptoms of mouth ulcers are tenderness, painful sores on the lining of the mouth, ulcers with a white centre, problems with chewing or tooth brushing because of the tenderness, sensitivity and pain when eating and drinking (especially salty, spicy and sour foods) and a loss of appetite.



Mouth ulcers can develop for no apparent reason in healthy people but there is a range of other factors that can cause them. These include:


* Oral trauma – such as that caused by accidental biting of the cheek, injury from a toothbrush (such as slipping while brushing), badly fitting dentures, braces, misaligned or sharp teeth damaging the gum.  

* Stress or anxiety.  

* Poor dental hygiene.  

* Irritation from strong antiseptics, such as mouthwashes  

* Reaction to certain medications, such as chemotherapeutic agents  

* Burns to the mouth from hot drinks or food.  

* A lack of iron or certain vitamins.  

* Various infections such as the oral thrush infection and herpes simplex viral infection (cold sores)

* Autoimmune diseases, such as AIDS.  

* Certain diseases such as diabetes, Coeliac disease, Crohn’s disease, cancer of  the lip – any disease which causes inflammation in the body or affects the immune system can cause a mouth ulcer  

* Hormonal changes – some women notice they develop prior to menstruation.


Aphthous ulcers appear as crops of small off-white sores. They affect about one-in-five adults but the cause is unknown. Because they can develop following times of stress or during a woman's period, some experts believe they're related to an immune system reaction since the immune system reacts to hormones and stress. The underlying trigger may be a virus or an allergic reaction.



Some of the investigations to help establish the cause of mouth ulcers include a physical examination. Mouth ulcers look different depending on their cause. If the ulcer is large and yellow, it is most likely caused by trauma. Cold sores inside the mouth tend to be numerous and spread around the gums, tongue, throat and inside of the cheeks. A fever also suggests the ulcers may be caused by a herpes simplex infection. Blood tests will indicate if there is any sign of infection and a skin biopsy (a small tag of tissue taken from the ulcer to be examined in a laboratory) may be taken to help determine the reason for the mouth ulcer.



Most mouth ulcers are harmless and heal by themselves in a few days. Other types of mouth ulcers, such as the aphthous variety or those caused by the herpes simplex infection need medical treatment. It isn’t possible to speed the recovery of mouth ulcers, but the symptoms can be managed and the risk of complications reduced.

* Avoid spicy and sour foods until the ulcers heal  

* Drinking plenty of fluids  

* Maintaining dental hygiene  

* Mouthwashes or Warm, slightly salted water to help clear bacteria during healing  

* Solutions, such as Difflam Anti-inflammatory solution or Difflam Anti-inflammatory and Antiseptic Solution.

* Over-the-counter pain relief creams and gels (antiseptics or steroid gels) such as Bonjela, Difflam Anti-inflammatory Anti-bacterial mouth gel and Kenalog  

* Treating aphthous ulcers with anti-inflammatory medication

* Using anti-viral or anti-fungal drugs for mouth ulcers resulting from disease or infection




Suggestions on how to reduce the likelihood of mouth ulcers include:

* Maintaining good standards of oral hygiene – brush your teeth at least twice every day, floss regularly, regularly visit the dentist

* Brush your teeth gently, taking care not to slip the brush

* Eat a well-balanced and nutritious diet

* Ensuring underlying medical conditions, such as diabetes mellitus and inflammatory bowel disease, are managed appropriately.

* Boost your immune system – immune enhancing herbs and supplements include Vitamins A, C, and Zinc as well as Echinacea. Two B Vitamins in particular, Folic Acid (Vitamin B9) and thiamine (Vitamin B1) have been shown to heal and prevent mouth ulcers.