The mouth is the common entrance to the respiratory and digestive tracts, so having oral problems, respiratory problems, and digestive problems can cause dry mouth and bitterness when waking up in the morning. Firstly, poor oral hygiene, accumulation of a large amount of plaque and calculus on the tooth surface near the gum margin, bright red gums, high edema, hypertrophy and obvious bleeding tendency, secretion of inflammatory gingival sulcus fluid, can lead to oral odor dry mouth and bitter symptoms, especially if you did not brush your teeth before going to bed the night before. Red and swollen, white foamy sputum in the morning, tonsil stones, soft palate prolapse, narrow airway and other physiological anatomical abnormalities will lead to open mouth breathing at night, dry mouth and bitterness in the morning is extremely obvious, the effect of brushing teeth is not good; gastrointestinal discomfort, gastric and bile reflux, etc., generally the reflux situation will increase at night, in the morning will obviously feel dry mouth and bitterness, sour and rotten hangover taste, no change after brushing teeth, eating party can It will not change after brushing the teeth and can be alleviated by eating. There is another saying in Chinese medicine that spleen deficiency and liver fire can lead to dry mouth and bitterness. Regardless of the cause, it is recommended that we go to the hospital in time for effective treatment to prevent the disease from progressing and endangering our health.