Sourness in the mouth after eating may be related to food factors, reflux esophagitis and other reasons. 1. Food factors: If you eat food with an acidic taste and don’t rinse your mouth in time after eating, you are likely to have an acidic feeling in your mouth. 2. Reflux esophagitis (GERD): When suffering from GERD, stomach contents mixed with stomach acid may reflux into the esophagus and the inside of the mouth after eating, which may stimulate the mouth and produce a sour feeling. It is recommended to rinse the mouth or brush the teeth in time after eating, if it can not be relieved, it is necessary to go to the regular hospital in time, to clarify the cause, and standardized treatment under the guidance of the doctor, so as not to delay the condition of the body to bring about adverse effects.