Bitter mouth and bad breath in the morning may be caused by uremia, but there are more causes of bitter mouth and bad breath, and the specific causes need to be determined according to professional examination results and cannot be generalized. Usually, bitter mouth and bad breath are caused by oral diseases, such as periodontitis, dental caries or oral mucosal lesions, etc. The symptoms can be effectively relieved by diligent tooth brushing and mouth rinsing. It may also be caused by digestive system diseases, such as gastric ulcer, gastroenteritis, indigestion, etc., which can cause abdominal distension and gas reflux in the abdomen, which can make bitterness and bad breath occur. If only once in a while you wake up early and feel bitter and bad breath, it may be related to diet, such as eating smelly food the night before, grapefruit, oranges, coffee, or smoking or drinking alcohol, which can occur. In addition, it may be due to cancer or uremia. Patients are advised to visit the gastroenterology or urology departments to improve relevant examinations for a clear diagnosis. In case of bitter mouth and bad breath, you can take Chinese herbal medicine under the guidance of a doctor to regulate it, and at the same time make good work and diet adjustments and maintain good oral hygiene.