What causes thrush? Most people have small amounts of the Candida fungus in the mouth, digestive tract and skin. They are normally kept in check by other bacteria and microorganisms in the body. When illnesses, stress, or medications disturb this balance, the fungus grows out of control and causes thrush.

How do you catch thrush?

It's possible for you to pass the fungus from one part of your body to another part of someone else's body. If you have oral thrush, a vaginal yeast infection, or a penile yeast infection, you can potentially pass the fungus to your partner through vaginal sex, anal sex, or oral sex.

Why do you get oral thrush?

Causes of oral thrush

Oral thrush and other yeast infections are caused by an overgrowth of the fungus Candida albicans (C. albicans). It's normal for a small amount of C. albicans to live in your mouth, without causing harm.