Bitter mouth in the morning is not necessarily gastritis, but can also be seen in liver and gallbladder diseases, oral diseases, etc. The specific diagnosis must be combined with other clinical manifestations, examination, etc., by a professional doctor. 1. Gastritis: Gastritis can cause morning sickness due to indigestion. In this case, the patient may also suffer from abdominal pain, bloating, nausea, acid reflux, loss of appetite and other digestive discomforts, and there may be abnormalities in Helicobacter pylori test, gastric fluid analysis, gastroscopy, and so on. 2. Other diseases: oral diseases (such as periodontitis, oral ulcers), liver and gallbladder diseases (such as cholecystitis, hepatitis), renal diseases (such as kidney stones, nephritis), taste nerve abnormalities (such as brain damage, endocrine disorders) can also lead to morning sickness. In such cases, the patient will have clinical manifestations of the corresponding organs and systems, and the above tests will not show any abnormality. Therefore, the bitter mouth in the morning is not absolutely gastritis, people with this symptom should consult a doctor in a timely manner to identify the cause and then under the guidance of the doctor to carry out the appropriate targeted treatment, do not blindly judge, dispose of their own, so as not to cause adverse consequences.