The causes of dry mouth and bitterness are strongly related to the gastrointestinal tract, gallbladder and endocrine diseases. If you suffer from dry mouth and bitterness, it is recommended that you first go to the hospital for a gastroscopy and liver and gallbladder ultrasound to clearly diagnose whether abnormalities in these two organs are the cause. You can also have a blood sugar test at the same time, because the symptoms of dry mouth are often related to elevated blood sugar. Chronic inflammation of the gallbladder and bile reflux due to food accumulation caused by the weakened digestive function of the gastrointestinal tract are some of the more common causes of bitter mouth. If it is clear that it is caused by these reasons, you can first use some anti-inflammatory drugs, such as quinolones and aminoglycosides, which can effectively improve the inflammation of the gallbladder, and you can also use gastrointestinal motility drugs, such as domperidone, which can reduce the bile reflux and relieve the symptoms of bitter mouth. If the dry mouth is caused by the lack of fluid, you can drink more water to relieve the symptoms of dry mouth. If the dry mouth is caused by endocrine disorders, such as diabetes, you should treat the symptoms by lowering blood sugar. In short, if you suffer from dry mouth and bitterness, you must do relevant examinations for gastrointestinal tract and gallbladder diseases, as well as laboratory tests for blood sugar and electrolytes.