Oral thrush
Key facts
- Oral thrush, also known as oral candidiasis, is a mouth infection caused by a yeast fungus known as candida.
- Many people have candida present in their mouth without experiencing any problems.
- Risk factors for developing oral thrush include diabetes, chronic illness and poor dental hygiene.
- Oral thrush can be treated with antifungal mouthwashes, ointments or oral medicines.
- See your doctor if you have severe symptoms of oral thrush or symptoms return after treatment.
What is oral thrush?
Oral thrush, also known as oral candidiasis, is an infection in your mouth caused by yeast (a type of fungus) known as candida.
Candida does not always cause symptoms.
Candida can cause problems when there is a change in the microbes (tiny living particles) living inside the mouth that reduces the number of ‘good’ bacteria and allows the candida to grow and multiply.
What causes oral thrush?
Oral thrush is caused by a yeast fungus called candida. There are a few different types of candida that can cause oral thrush. Candida albicans is the most common cause.
Who gets oral thrush?
Most of the population have candida in their digestive tract and don’t experience any problems. If you are healthy, your immune system usually protects you from developing an overgrowth of candida.
You are more likely to develop symptoms of oral thrush if you:
- are very young or older in age
- have some chronic medical conditions, such as diabetes, cancer or untreated HIV
- take certain medicines such as antibiotics (especially for long periods of time) and inhaled corticosteroids (used in lung conditions such as asthma)
- smoke
- have a dry mouth, due to problems with your salivary glands or some medicines such as antihistamines and diuretics
- suffer malnutrition
- wear dentures (especially if they do not fit well) or have poor oral hygiene
Newborn babies and infants can catch oral thrush from their mothers when breastfeeding.
Read more about oral thrush in children.
What are the symptoms of oral thrush?
Oral thrush can cause white patches in your mouth that can be wiped away to leave red areas that may bleed.
Other symptoms may include:
- pain or burning in the mouth
- an unpleasant taste in your mouth
- changes to your sense of taste
- a red mouth or throat
- cracks at the corners of the mouth
If you are concerned that you might have oral thrush, check your symptoms with healthdirect’s online Symptom Checker to get advice on when to seek medical attention.
CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.
When should I see my doctor?
You should see your doctor if you are concerned that you have oral thrush.
You should also see your doctor if you’re not sure what is causing your symptoms, if your symptoms are severe or if they come back after treatment.
Many treatments for oral thrush are available at your local pharmacy without a doctor’s prescription. If you have had thrush before and know what it feels like, you may decide to consult your pharmacist and consider an over-the-counter treatment.
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How is oral thrush diagnosed?
Your doctor can diagnose oral thrush by asking about your symptoms and examining your mouth.
If your symptoms do not get better with treatment or the diagnosis isn’t clear, your doctor may take a swab of your sores to be checked in a lab.
This can confirm the diagnosis and help choose the best treatment for you.
In rare cases, your doctor may refer you for an endoscopy to see if you also have thrush in your oesophagus or further down your digestive tract.
How is oral thrush treated?
Oral thrush is usually treated with topical antifungal treatments such as antifungal mouthwash, ointment or lozenges.
In some cases, your doctor may prescribe antifungal medicine in the form of a tablet.
You will usually need to continue treatment for at least one week. Every treatment is different, so ask your doctor or pharmacist if you have any questions.
How can I prevent oral thrush?
Here are some tips to prevent oral thrush:
- Brush your teeth regularly.
- Use warm saline water as mouthwash. Avoid using antiseptic mouthwashes. These can change the balance of ‘good’ bacteria in your mouth, allowing candida to grow and cause oral thrush.
- If you wear dentures, make sure that they are cleaned properly, and that the skin under the dentures is also clean. Rinse your mouth out after every meal. Take your dentures out overnight.
- If you use inhaled corticosteroids, rinse your mouth well with water after each inhalation.
- Drink plenty of water.
- If you smoke, try to cut down or quit. Smoking can make symptoms worse.
- Reduce the amount of sugar in your diet.
Resources and support
DermNetNZ has more information about oral thrush.
If you or someone you know has diabetes, learn more about protecting your oral health at Diabetes Australia.
If you or someone you know has asthma, the Australian Dental Association has information about preventing oral thrush.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: May 2024
