Gastritis occurs when the lining of the stomach becomes inflamed or swollen.

Gastritis can last for only a short time (acute gastritis), or linger for months to years (chronic gastritis).

The most common causes of gastritis are:

• Certain medications, such as aspirin, ibuprofen, or naproxen, when taken over a longer period of time
• Drinking too much alcohol
• Infection of the stomach with a bacteria called Helicobacter pylori

Less common causes are:

• Autoimmune disorders (such as pernicious anemia)
• Backflow of bile into the stomach (bile reflux)
• Cocaine abuse
• Eating or drinking caustic or corrosive substances (such as poisons)
• Extreme stress
• Viral infection, such as cytomegalovirus and herpes simplex virus, especially in people with a weak immune system

Trauma or a severe, sudden illness such as major surgery, kidney failure, or being placed on a breathing machine may cause gastritis.

Many people with gastritis do not have any symptoms.

Symptoms you may notice are:

• Loss of appetite
• Nausea and vomiting
• Pain in the upper part of the belly or abdomen

If gastritis is causing bleeding from the lining of the stomach, symptoms may include:

• Black stools
• Vomiting blood or coffee-ground like material

Tests that may be needed are:

• Complete blood count (CBC) to check for anemia or low blood count
• Examination of the stomach with an endoscope (esophagogastroduodenoscopy or EGD)
• H. pylori tests
• Stool test to check for small amounts of blood in the stools, which may be a sign of bleeding in the stomach

Treatment depends on the specific cause. Some of the causes will disappear over time.

You may need to stop taking aspirin, ibuprofen, naproxen, or other medicines that may be causing gastritis, but only after you talk with your health care provider.

You may use other over-the-counter and prescription drugs that decrease the amount of acid in the stomach, such as:

• Antacids
• H2 antagonists: famotidine (Pepsid), cimetidine (Tagamet), ranitidine (Zantac), and nizatidine (Axid)
• Proton pump inhibitors (PPIs) -- omeprazole (Prilosec), esomeprazole (Nexium), iansoprazole (Prevacid), rabeprazole (AcipHex), and pantoprazole (Protonix)

Antacids may be used to treat chronic gastritis caused by infection with Helicobacter pylori bacteria.

The outlook depends on the cause, but is usually good.

Blood loss and increased risk of gastric cancer are possible complications.

Call for an appointment with your health care provider if you develop:

• Pain in the upper part of the belly or abdomen that does not go away
• Black or tarry stools
• Vomiting blood or coffee-ground-like material

Avoid long-term use of irritants (such as aspirin, anti-inflammatory drugs, or alcohol).

Kuipers, E. Acid peptic disease. In: Goldman L, Ausiello D. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 141.

Lee EL, Feldman M. Gastritis and gastropathies. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier;2010:chap 51.