Thrush is a common fungal infection caused by overgrowth of Candida species (most often Candida albicans), a yeast naturally present in the mouth, gut, and skin. Oral thrush appears as creamy white patches or plaques on the tongue, inner cheeks, gums, tonsils, roof of the mouth, or throat; these patches may be slightly raised, resemble cottage cheese, and can sometimes be scraped off, leaving red, raw, or bleeding areas underneath. It often causes soreness, a cotton-like feeling in the mouth, loss of taste, redness, cracking at the corners of the mouth (angular cheilitis), or mild burning/pain while eating or swallowing. In infants, it is very common and may show as white patches with fussiness during feeding; in adults, it frequently occurs in those with weakened immunity (e.g., babies, elderly, people with diabetes, HIV, cancer treatment, inhaled corticosteroids, or antibiotic use that disrupts normal flora).