There are many causes of bad breath in men, such as bad habits, poor diet, oral diseases, and digestive disorders. There is no gender difference in the causes of bad breath. 1. Bad habits: usually do not like brushing teeth, long-term smoking and drinking, etc., can cause bad breath phenomenon, usually after correcting the habit can be gradually improved. 2. Improper diet: bad breath may be caused by eating garlic, onion, durian, onion and other foods, usually after cleaning the mouth or avoiding food will be relieved. 3. Oral diseases: Diseases such as dental caries and periodontitis can also cause a large number of bacterial growth, thus causing bad breath. 4. Digestive tract diseases: reflux esophagitis, reflux gastritis, Helicobacter pylori, etc., can form sulfur compounds, which can cause bad breath. There are many reasons for bad breath, after the symptoms, it is recommended to go to the hospital in a timely manner to improve the examination, after a clear diagnosis to give standardized treatment, not to private treatment, so as not to lead to adverse consequences.