Oral thrush is a yeast infection caused by the fungus Candida. It results in white or gray lesions on the mouth lining, gums and the tongue. Candida levels are usually kept in balance by the immune system and friendly bacteria in the mouth. Oral thrush can develop if you have high blood sugar, during times of illness, or if you're taking certain medications, including steroids, antibiotics or chemotherapy. Hydrogen peroxide is a traditional treatment for oral thrush.
Buy a bottle of 3 percent hydrogen peroxide from a department store or pharmacy. This is the standard commercial form of hydrogen peroxide solution, and a 16-oz. bottle of it is inexpensive, typically less than $3 as of 2009.
Use a soft toothbrush for brushing. Oral thrush sores can be painful, and a soft toothbrush is easy on your gums. After brushing, pour a small amount of hydrogen peroxide into a paper or foam cup and swish your toothbrush for several seconds to disinfect it.
Add 3 parts warm water to 1 part hydrogen peroxide in another cup. Using 3 tbsp. water and 1 tbsp. hydrogen peroxide is a good place to start; you can double the amount next time if you need more. Rinse your mouth with the mixture, swishing it all around several times. Spit all the liquid out into the sink.
Rinse your mouth with hydrogen peroxide four times daily, first in the morning and and the fourth time just before going to bed.
Don't swallow any of the hydrogen peroxide solution.