Inflammation of the stomach lining. White blood cells move into the wall of the stomach as a response to some type of injury; this does not mean that there is an ulcer or cancer – it is simply inflammation, either acute or chronic. Symptoms depend on how acute it is and how long it has been present. In the acute phase, there may be pain in the upper abdomen, nausea and vomiting. In the chronic phase, the pain may be dull and there may be loss of appetite with a feeling of fullness after only a few bites of food. Very often, there are no symptoms at all. If the pain is severe, there may be an ulcer as well as gastritis.