Spit in the middle of the night with blood during the day is fine because of chronic pharyngitis, periodontitis or gingivitis. 1. Chronic pharyngitis: mainly due to upper respiratory tract infections, such patients at night because of the inflammatory secretions in the throat can not be discharged in a timely manner, it is likely that there will be an irritating cough, which is manifested as the phenomenon of blood in saliva. 2. Periodontitis: mainly caused by not paying attention to personal oral hygiene, the patient may have red, swollen gums, bleeding phenomenon, due to drinking more water during the day, may not be able to observe the phenomenon of blood in saliva. 3. Gingivitis: mainly due to plaque caused by the patient in the daytime due to eating a lot of food, can not observe the phenomenon of blood in the saliva, the middle of the night basically do not eat, is likely to show the phenomenon of spit with blood. There are many other reasons for spitting blood in saliva in the middle of the night and nothing during the day, it is recommended to go to the hospital in time, after clarifying the cause of the disease, standardized treatment under the guidance of a professional doctor.