Waking up every morning with bad breath may be caused by oral diseases, gastrointestinal diseases, and systemic diseases, and it is recommended to consult a doctor in time for examination. 1. Oral disease: when there is caries, there is a large number of bacterial growth in the area of caries, which corrodes the teeth and may produce a special odor and cause bad breath. 2. Gastrointestinal diseases: Having chronic gastritis, gastroesophageal reflux and other diseases may lead to bad breath. Patients with chronic gastritis are prone to gastric distention and indigestion, which cause a lot of gas to be produced in the stomach, and through gastroesophageal reflux, these gases will enter the oral cavity to be discharged out of the body, resulting in bad breath, which will be more pronounced in the morning when you first wake up. 3. systemic diseases: for example, liver disease, there may be liver odor, because of liver function abnormalities lead to increased metabolites of the liver caused by bad breath in the morning. In addition to the above factors, do not rule out is caused by other factors, such as gingivitis, dental calculus, diabetes, etc.; should consult a doctor in a timely manner to clarify the cause, and take active treatment.