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Thrush is essentially a yeast infection of the mouth, and those with weaker immune systems, such as babies and the elderly, are susceptible to an overgrowth of candida that can result in making thrush contagious. But in reality, anyone with the right conditions in their mouth can both house and transmit the yeast responsible for thrush. By understanding the condition – and what makes it contagious – you can decide the level of contact you have with someone who has thrush.

Thrush 101

The Centers for Disease Control and Prevention (CDC) notes that everyone has some yeast, or candida, in their mouths. It’s found on the skin and mucous membranes in your mouth and is usually harmless. Unfortunately, certain conditions can cause an imbalance in the environment of the mouth, resulting in the ability for the yeast to multiply. When there’s too much yeast, it creates a fungal infection called oropharyngeal candidiasis, or thrush. Symptoms include:

  • White patches on the tongue or oral mucous membranes
  • Redness and soreness in the mouth
  • Cracking at the corners of the mouth
  • Difficulty and pain when swallowing

Your doctor can diagnose thrush by taking a culture of your mouth and then comparing the results to your symptoms. Thrush is treated with an anti-fungal that is swished around the mouth to kill the fungus and restore balance.

Risk Factors

A compromised immune system and the right environment helps the yeast to flourish and make thrush contagious. When taking certain medications, like antibiotics or corticosteroids, for example, your body might produce more yeast than usual. Babies are susceptible to thrush, as are those with AIDS and denture-wearers. The CDC estimates that between 5 and 7 per cent of babies younger than one month old, between 9 and 31 per cent of AIDS patients, and 20 per cent of cancer patients will develop thrush.

The District of Columbia Department of Health warns that thrush can be transmitted through the secretions of an infected person. Thrush can be contagious, but it’s unlike other contagious germs and bacteria. That’s because, in order for the yeast to flourish and overproduce, both parties would have to have the ideal oral environment. Since yeast is present in everyone’s mouth, kissing a person with thrush, for example, wouldn’t automatically transmit the fungus.


If you’re worried about contracting thrush from an infected person, you may want to avoid coming in contact with their saliva. Avoid kissing and make sure to wash your hands frequently when you’ve come in contact with someone who has thrush. The CDC suggests that good oral hygiene can also help to prevent thrush in individuals with compromised immune systems, so if you’re worried you’re at risk, continue habits like brushing twice daily and swishing with mouthwash.

Thrush can be painful and inconvenient, so it’s important to understand your risk. While it’s not likely to be contagious to the average healthy person, it is still transmittable, especially for those at risk. If someone you know has thrush, it’s best to be careful until it clears.