###Human: Is it possible to get halitosis because of gastritis? ###Assistant: Hi. Halitosis or bad breath usually originates from oral or nasal passages. The cause of it is bacterial decay of residual food and debris. Most common causes of halitosis are periodontal diseases, dental caries, oral cavity infection, and coated or uncleaned tongue or decreased salivation. Other causes which are thought of after ruling out the above are a tonsillar abscess, any esophageal pathology which allows collection of residual food in esophageal like a diverticulum or motility disorder like achalasia. Lung pathology like lung abscess can also be the cause of halitosis. Gastritis due to H.pylori can also cause halitosis. Also, bezoars in the stomach can also be a cause.