There is no best way to cure bad breath, and the presence of bad breath needs to be treated according to the cause. Halitosis may be physiological, and may be caused by oral diseases or gastric diseases, medication can be used to treat the original disease. 1. Physiological bad breath: consumption of food with irritating odor, such as garlic, scallions, leeks, stinky tofu, etc. can cause temporary bad breath; not diligent brushing, food residues left in the mouth, the bacterial fermentation can produce oral odor. By avoiding stimulating foods and brushing teeth after meals, morning and evening, bad breath can be avoided. 2. Pathological bad breath (1) Oral diseases: such as gingivitis, periodontitis, oral ulcers and so on. Gingivitis, periodontitis can be anti-inflammatory treatment, periodontal treatment, oral drugs such as amoxicillin, metronidazole, local application of iodine glycerin for anti-inflammatory, periodontal treatment, including scaling, scraping and so on. Mouth ulcers can be treated with watermelon cream spray and vitamin supplements. (2) Gastric diseases: such as gastrointestinal dysfunction, intestinal flora imbalance. Patients with gastrointestinal dysfunction can use compound digestive enzyme capsules, vitamin B1 tablets and other drugs to regulate the stomach and intestines, promote intestinal peristalsis and laxation, and relieve bad breath. For patients with intestinal flora imbalance, compound probiotics and bifidobacteria capsules can be taken to balance the gastrointestinal flora and relieve bad breath. The occurrence of bad breath, excluding physiological factors, the patient should consult a doctor in a timely manner to identify the cause, active treatment can remove bad breath, the use of drugs need to follow the doctor’s instructions.