There is no significant difference between men and women in the causes of bad breath. There are many causes of bad breath in men, such as bad habits, oral diseases, digestive diseases and so on. 1. Bad habits: Eating foods such as onions and garlic, or long-term smoking and not brushing your teeth can lead to bad breath. 2. Oral diseases: periodontitis, dental caries, pulpitis and other diseases can also cause bad breath. Especially dental caries will lead to many residual substances in the cavity, if not cleaned up, bad breath will occur. 3. Digestive tract diseases: gastric ulcer, gastritis, duodenal ulcer, reflux esophagitis and other diseases can also cause bad breath in men, due to acid reflux, sulfur compounds, etc., can cause the phenomenon. There are many causes of bad breath in men, after the symptoms should be timely to go to the hospital to improve the examination, follow the doctor’s instructions to take standardized treatment, do not delay the condition, so as not to lead to adverse consequences.