The appearance of gastritis can cause bad breath. After the appearance of gastritis, it is easy to cause lesions in the gastric mucosa due to bacterial infection, causing damage to the mucosa, resulting in bad breath due to indigestion. After the appearance of gastritis, the patient’s peristaltic ability will be reduced, or even slowly deteriorate, which will easily cause food indigestion, excessive accumulation in the intestines, resulting in more and more bacterial growth, resulting in bad breath and other conditions. The condition is difficult to treat, so after gastritis, the patient will have bad breath because of the decrease in the peristaltic power of the stomach, which affects the intestinal health and also the oral hygiene.