If you wake up in the morning with a bitter mouth, you need to consider whether there is inflammation of the mouth, reflux of bile or gastrointestinal digestive malfunction, etc. First of all, oral examination should be conducted to see if there is gingivitis, periodontitis, mouth ulcers, etc. It is necessary to further take care of the oral cavity, brush the teeth and rinse the mouth regularly, and also pay attention to the improvement of dietary habits, including quitting smoking, quitting alcohol, and reducing the consumption of greasy, fried, spicy and stimulating foods, and observe whether the symptoms of bitter mouth improve. If there is still no improvement, it is necessary to consider whether there is bile reflux or digestive malfunction, etc. Further gastroscopy can be performed to assess the condition of the stomach, whether there is bile reflux gastritis or gastric ulcer, etc. If symptoms are present, further treatment is needed. Ultrasound examination of the liver and biliary tract can also be performed to see if there are any diseases of the biliary system that require treatment.