Mouth ooze is mainly seen in the following clinical conditions: 1. congenital heart disease. For example, atrial septal defect or ventricular septal defect, accompanied by right-to-left shunt, resulting in a large amount of venous blood without oxygenation directly into the arteries, directly supplying various organs and tissues throughout the body, the lips are prone to mouth ooze due to lack of oxygen. 2, lung diseases. The most common are chronic obstructive pulmonary disease, diffuse interstitial lung fibrosis, pulmonary embolism, etc. These diseases affect the blood in the lungs for oxygenation, and finally prone to hypoxemia, also easy to show the mouth ooze. 3, heart failure. Especially seen in left heart failure, because the amount of blood shot from the left ventricle to the aorta is reduced, the amount of blood in the lungs for oxygenation will be reduced, which will also cause ischemia and hypoxia in various tissues and organs throughout the body, which can also appear as mouth ooze.