Oral thrush happens when a yeast infection develops inside your mouth. It’s also known as oral candidiasis, oropharyngeal candidiasis, or simply thrush.
Oral thrush most often occurs in infants and toddlers. It causes white or yellowish bumps to form on the inner cheeks and tongue. Those bumps usually go away with treatment.
The infection is typically mild and rarely causes serious problems. But in people with weakened immune systems, it can spread to other parts of the body.