There are several reasons for male bad breath: 1, gastric disease, gastritis, gastric ulcer, duodenal ulcer can lead to bad breath, infection caused by Helicobacter pylori gastric disease has a higher probability of halitosis, because the infection bacteria stomach will produce a lot of sulfide, eradication of the symptoms of halitosis will be significantly reduced after the Helicobacter oil. 2, food, onions, garlic contains special odor substances will also lead to bad breath. 3, cold, nasal congestion. People in the cold, nasal congestion will breathe through the mouth, the mouth will be much less water, the self-cleaning function of the mouth will decline, bacteria will increase a lot, plus residual food residues in the mouth will appear bad breath. 4, sinusitis, sinus secretions in the role of bacteria will produce a very unpleasant smell, unpleasant secretions into the mouth will lead to bad breath. 5, periodontitis, because periodontitis will lead to the oral cavity Bacteria increase, the bacterial decomposition of saliva in the mouth, food residues will produce sulfide resulting in bad breath.