- Gastritis refers to inflammation of the gastric mucosa. Although 'gastritis' is categorized into 'chronic' and 'acute', these labels do not refer to unique pathophysiological entities. Rather, they are histological terms distinguishing whether the inflammation seen in the gastric mucosa has a more acute inflammatory or chronic inflammatory character. Indeed, several different etiologies can give rise to either acute or chronic gastritis. It should be pointed out that chronic gastritis is much more common that acute gastritis.