Sleeping at night dry mouth sputum turns red may be environmental factors (environmental dryness, capillary rupture in the airways), may also be pathological factors (such as tuberculosis, periodontitis, etc.), need to be specifically analyzed. 1. Environmental factors: when the air humidity in the sleeping environment is low at night, it can cause excessive loss of respiratory tract water, dry respiratory mucosa, capillary rupture, so the phenomenon of dry sputum turning red will occur, open the air humidifier to increase the humidity of the surrounding environment can be improved. 2. Pathological: tuberculosis, tuberculosis foci bleeding, there will be dry mouth sputum red symptoms, but also accompanied by fatigue, low-grade fever and other symptoms, tuberculin test and other tests can assist in the diagnosis; periodontitis, oral inflammation is heavy, gum bleeding, phlegm coughed up by the oral cavity after mixing the blood, there will be a dry mouth sputum red symptoms, need to be oral specialist clinic clear and treatment. There are many causes of dry mouth and red sputum at night, so it is recommended to consult a doctor in a timely manner, except for organic lesions, to avoid delays in the condition.