Also known as candidiasis, oral thrush is a yeast infection that develops inside the mouth. The condition results in white patches that are often cottage cheese-like in consistency on the surfaces of the mouth and tongue. Oral thrush is most commonly seen in infants and the elderly, especially denture wearers, or in people with weakened immune systems. People with diabetes and people taking inhaled steroids for asthma or lung disease can also get thrush. Oral thrush is more likely to occur after the use of antibiotics, which may kill the "good" bacteria in the mouth.