Medical 3% hydrogen peroxide (hydrogen peroxide) 100ml. morning and evening after gargling take about 10ml, add water 30~40ml dilution, gargle in parts, about 2~3min, and even use 3~5 days to stop. It can be used repeatedly when bad breath occurs again. Bad breath (halitosis, bad breath) has many causes. Ancient and modern, both patients and doctors generally believe that bad breath is caused by gastrointestinal disease. However, this view is indeed wrong. Research in the last two decades has thoroughly proved that most bad breath is oral in origin, and the root cause is the overgrowth of anaerobic bacteria on the tongue, without gingivitis, the naked eye can hardly see any abnormalities in the mouth, and the complication of gingivitis is also seen as a gastrointestinal “fire”. It is true that there are many cases of gastric disease cured bad breath also disappeared, but the reason for this is the use of antibacterial drugs on the tongue of anaerobic bacteria also have an inhibitory effect, especially metronidazole. Hydrogen peroxide (H2O2) has a strong oxidizing effect, so it can deodorize, inhibit and kill anaerobic bacteria. Practice has proved to be effective. However, it should be noted that hydrogen peroxide is irritating and should not be used continuously for a long time to avoid side effects such as hypertrophy of the tongue, nor should non-medical products with a concentration greater than 3% be used to avoid burns. In addition, patients should visit a stomatologist before deciding whether to use this formula.