Bad breath caused by gastrointestinal can be relieved by morpholine, omeprazole, bismuth citrate potassium. There are more causes, such as oral diseases, poor gastrointestinal, and inattention to oral hygiene. Bad breath caused by poor gastrointestinal, mainly and bad lifestyle, abdominal cold, food stagnation in the stomach is not easy to digest, there will be dry mouth, bad breath, etc. Bad breath is mainly symptomatic treatment. Some people have abnormal and unformed stools caused by dysbiosis of intestinal flora, which is treated by oral probiotics, such as bifidobacteria. When dry stool occurs, by maintaining a regular diet of three meals and eating more coarse fiber foods, together with morpholine treatment, it can promote peristalsis of the intestines and stomach to help empty the stomach and reduce the symptoms of bad breath. Bad breath caused by gastritis should be treated with drugs that inhibit gastric acid secretion, such as omeprazole, and also with drugs that protect the gastric mucosa, such as bismuth potassium citrate, which can reduce the symptoms of pain, burning sensation, heartburn and acid reflux in the stomach.