The first mouthful of saliva in the morning has a color and you need to see if it is accompanied by redness or brownness. If these problems are present, it may be due to a disease such as an ulcer in the mouth, or some bleeding gums, and you can go to a dentist for a definitive diagnosis. If oral problems are ruled out, the bleeding may be due to respiratory or gastrointestinal diseases. Respiratory system diseases should be accompanied by coughing and coughing up sputum. Bronchiectasis or tuberculosis may be considered, and the diagnosis can be confirmed by a chest X-ray or a tuberculin test. Gastrointestinal system diseases may be caused by esophagitis or broken digestive tract mucosa, which can be diagnosed by gastroscopy and treated with drugs to protect the digestive tract mucosa.