Sourness on both sides of the tongue may be related to diet, excessive gastric acid secretion, atrophic lingual inflammation and other reasons. 1. Diet: acidity on both sides of the tongue may be related to daily diet, such as eating a large amount of lemon and other acidic food, it is easy to appear the symptoms of acidity on both sides of the tongue. 2. Excessive secretion of gastric acid: Sourness on both sides of the tongue may be related to excessive secretion of gastric acid. Under the influence of reflux esophagitis and other diseases, gastric acid is secreted excessively, and the excess gastric acid returns to the mouth through burping and so on, and the tongue will feel sour. 3. Atrophic lingual inflammation: Sourness on both sides of the tongue may also be due to atrophic lingual inflammation of the tongue, in which the taste buds feel abnormal and the tongue feels sour. If you suspect that the acidity on both sides of the tongue is related to the disease, you can consider going to the regular hospital for a detailed examination.