GAST and gastritis: Inflammation of the gastric mucosa results from an imbalance between mucosal defensive and aggressive factors such as gastric acidity, mucus-bicarbonate barrier, and gastric hormones (i.e., gastrin, pepsinogens I, II).[1,2] The impaired mucosal defensive mechanism can cause mucosal injury which can result in gastritis or gastric ulcer even in children.[3,4] Acute gastritis refers to a state of acute inflammation in the gastric mucosa, redness, edema, and infiltration of acute cells.