Gastritis

Gastritis is a general term for any disorder that affects digestion, causes stomach pain, and is the result of the effect of stomach acid or other caustic substances on the stomach lining and esophagus. Gastritis can be acute or chronic, and can vary widely in degree of pain and length of attack. There are several underlying conditions that can cause gastritis, in roughly increasing order of severity they are:
*Indigestion, caused by ingesting too much food or liquid. It is often common if the patient exercises after a heavy meal. This resolve itself if the patient stops eating and rests.
*Acid Indigestion, caused by the temporary overproduction of stomach acid in response to certain foods, such as those with a high acid content or those that contain a lot of spices. Treatment is antacids.
*Acid reflux disease or gastro-esophagal reflux disease, caused by a consistent overproduction of acid by the stomach which splashes onto the esophagus. Treatment is proton pump inhibitors which prevent the production of stomach acid. Acid reflux is a serious condition and can result in damage to the esophagus.
*Heliobacter pylori infection, caused by exposure to an acid-loving bacteria (most bacteria are destroyed by acid). The bacteria affect the production of mucous and expose the stomach lining directly to acid. Treatment is a one-week course of two different antibiotics.
*Gastric ulcer, caused by a H. pylori infection that has allowed stomach acid to eat through the stomach lining. The ulcer will bleed into the stomach and could become perforated, resulting in peritonitis and sepsis. This can be a life-threatening condition. Treatment is hospitalization and antibiotics.
Several medications, notably aspirin, can also cause gastritis.
Gastritis at Wikipedia
What is the Gastritis (in Spanish)