Wake up after sleep a spit with blood during the day and nothing may be dry respiratory mucous membrane bleeding, periodontal disease or gastrointestinal disease, need to be analyzed specifically. 1. Respiratory mucosal dryness and bleeding: because of the night sleep environment is dry, breathing and evaporate a lot of water, resulting in respiratory mucosal dryness, capillary rupture and bleeding, can also be accompanied by dry mouth, dry throat and other symptoms, drink more water or increase the humidity of the environment can be improved. 2. Periodontal disease: periodontal disease such as periodontitis can occur when the gums bleed, wake up after a spit can be blood, due to bleeding is not large, daytime brushing can be no obvious bleeding, may be accompanied by swollen and painful gums, oral odor and other symptoms, the need for scaling and other professional treatment of stomatology. 3. Gastrointestinal disorders: Gastrointestinal disorders such as reflux esophagitis can be accompanied by acid reflux, heartburn, chest pain and other symptoms after lying down at night, gastric acid reflux to the esophagus, which stimulates the mucous membrane of the gastrointestinal tract and leads to bleeding, and it can be improved by the upright position in the daytime, and gastroscopy and other tests can be used to assist in making a clear diagnosis. There are many reasons why there is blood in the mouth as soon as you wake up from sleep, it is recommended to consult a doctor in time to clarify the cause of the disease and actively treat it.