Oral thrush is caused by the parasitic proliferation of Candida albicans in the mucous membrane of the mouth. It is a secondary infection typically seen in individuals with weakened immune systems or those who have been using antibiotics for an extended period. In such cases, initially, one can use a 2.5% sodium bicarbonate solution to rinse the mouth, specifically targeting the areas affected by thrush. After meals, crush nystatin tablets and apply the powder to the areas with thrush, using this method three times a day. Additionally, taking probiotics orally, such as Bifidobacteria, can aid in treatment. Generally, these measures can control the condition within 3 to 5 days.