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Nimish Vakil

, MD, University of Wisconsin School of Medicine and Public Health

Reviewed/Revised Mar 2023
Topic Resources

Gastritis is inflammation of the stomach lining.

  • The inflammation can be caused by many factors, including infection, stress resulting from severe illness, injury, use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) alcohol, and disorders of the immune system.

  • When symptoms of gastritis do occur, they include abdominal pain or discomfort and sometimes nausea or vomiting.

  • Doctors often base the diagnosis on the person's symptoms, but sometimes they need to examine the stomach with a flexible viewing tube (upper endoscopy).

  • Treatment is with medications that reduce stomach acid and sometimes antibiotics.

The stomach lining resists irritation and can usually withstand very strong acid. Nevertheless, in gastritis, the stomach lining becomes irritated and inflamed.

The Stomach

Gastritis is divided into two categories based on how severe it is:

  • Erosive

  • Nonerosive

Erosive gastritis is more severe than nonerosive gastritis. This form involves both inflammation and wearing away (erosion) of the stomach lining. Erosive gastritis typically develops suddenly (called acute erosive gastritis) but may develop slowly (called chronic erosive gastritis), usually in people who are otherwise healthy.

Nonerosive gastritis is characterized by changes in the stomach lining that range from wasting away (atrophy) of the stomach lining to transformation of stomach tissue into another type of intestinal tissue (metaplasia). Often, several types of white blood cells accumulate in the stomach and cause varying degrees of inflammation. Inflammation can occur in the entire stomach or only in certain parts.

Causes of Gastritis

The specific types of gastritis are caused by many factors, including infection, stress resulting from severe illness, injury, certain medications (such as aspirin and other nonsteroidal anti-inflammatory drugs [ NSAIDs Nonsteroidal Anti-Inflammatory Drugs Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more ]), alcohol, and disorders of the immune system.

Erosive gastritis is commonly caused by alcohol, stress resulting from severe illness, and irritants such as medications, especially aspirin and other NSAIDs. Less common causes include Crohn disease Crohn Disease Crohn disease is an inflammatory bowel disease where chronic inflammation typically involves the lower part of the small intestine, the large intestine, or both and may affect any part of the... read more Crohn Disease , radiation, bacterial and viral infections (such as cytomegalovirus Cytomegalovirus (CMV) Infection Cytomegalovirus infection is a common herpesvirus infection with a wide range of symptoms: from no symptoms to fever and fatigue (resembling infectious mononucleosis) to severe symptoms involving... read more ), the ingestion of corrosive substances, and direct injuries (such as by the insertion of a nasogastric tube). In some people, even a baby aspirin taken daily can injure the stomach lining.

Infectious gastritis not caused by Helicobacter pylori is rare.

Viral gastritis or fungal gastritis may develop in people who have or have had a prolonged illness or an impaired immune system, such as those who have AIDS or cancer or those who take immunosuppressant medications Some Drugs That Can Cause Immunodeficiency Some Drugs That Can Cause Immunodeficiency .

Acute stress gastritis, a form of erosive gastritis, is caused by a sudden illness or injury. The injury may not even be to the stomach. For example, extensive skin burns, head injuries, and injuries involving major bleeding are typical causes. Exactly why serious illness can lead to gastritis is not known but may be related to decreased blood flow to the stomach, an increase in the amount of acid in the stomach, and/or to impairment of the stomach lining's ability to protect and renew itself.

Postgastrectomy gastritis occurs in people who have had part of their stomach surgically removed (a procedure called partial gastrectomy). The inflammation usually occurs where tissue has been sewn back together. Postgastrectomy gastritis is thought to result when surgery impairs blood flow to the stomach lining or exposes the stomach lining to an excessive amount of bile (the greenish yellow digestive fluid produced by the liver).

Atrophic gastritis causes the stomach lining to become very thin (atrophic) and to lose many or all of the cells that produce acid and enzymes. This condition can occur when antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more Antibodies attack the stomach lining (termed autoimmune metaplastic atrophic gastritis). Atrophic gastritis can also occur in some people who are chronically infected with H. pylori bacteria. It also tends to occur in people who have had part of their stomach removed.

Eosinophilic gastritis may result from an allergic reaction to an infestation with roundworms, but usually the cause is unknown. In this type of gastritis, eosinophils (a type of white blood cell) accumulate in the stomach wall.

Ménétrier disease, a rare disorder whose cause is unknown, is a type of gastritis in which the stomach wall develops thick, large folds and fluid-filled cysts. The disease may be due to an abnormal immune reaction and has also been associated with Helicobacter pylori infection Helicobacter pylori Infection Helicobacter pylori (H. pylori) infection is a bacterial infection that causes stomach inflammation ( gastritis), peptic ulcer disease, and certain types of stomach cancer. The... read more .

Symptoms of Gastritis

Gastritis usually causes no symptoms. When symptoms do occur, they vary depending on the cause and may include pain or discomfort or nausea or vomiting, problems that are often simply referred to as indigestion (dyspepsia).

Nausea and intermittent vomiting can result from more severe forms of gastritis such as erosive gastritis and radiation gastritis.

Indigestion Indigestion Indigestion is pain or discomfort in the upper abdomen. People may also describe the sensation as gassiness, a sense of fullness, or gnawing or burning. The sense of fullness may occur after... read more can occur, especially with erosive gastritis, radiation gastritis, postgastrectomy gastritis, and atrophic gastritis. Very mild indigestion also occurs with acute stress gastritis.

Complications of gastritis

Complications of gastritis include

  • Bleeding

  • Ulcers

  • Narrowing of the passage out of the stomach

Acute stress gastritis may lead to bleeding within a few days after an illness or injury, whereas bleeding tends to develop more slowly in the case of chronic erosive gastritis or radiation gastritis. If bleeding is mild and slow, people may have no symptoms or may notice only black stool (melena), caused by the black color of digested blood. If bleeding is more rapid, people may vomit blood or pass blood in their stool. Persistent bleeding can lead to symptoms of anemia Overview of Anemia Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more , including fatigue, weakness, and light-headedness.

Gastritis can lead to stomach ulcers Peptic Ulcer Disease A peptic ulcer is a round or oval sore where the lining of the stomach or duodenum has been eaten away by stomach acid and digestive juices. Peptic ulcers can result from infection with Helicobacter... read more Peptic Ulcer Disease (gastric ulcers), which may cause the symptoms to get worse. If an ulcer goes through (perforates) the stomach wall, stomach contents may spill into the abdominal cavity, resulting in inflammation and usually infection of the lining of the abdominal cavity (peritonitis Peritonitis Abdominal pain is common and often minor. Severe abdominal pain that comes on quickly, however, almost always indicates a significant problem. The pain may be the only sign of the need for surgery... read more ) and serious illness, with sudden worsening of pain.

Some complications of gastritis are slow to develop. The scarring and narrowing of the stomach outlet that can result from gastritis, especially from radiation gastritis and eosinophilic gastritis, can cause severe nausea and frequent vomiting.

In Ménétrier disease, fluid retention and swelling of the tissues (edema) may occur because of loss of protein from the inflamed stomach lining.

Postgastrectomy gastritis and atrophic gastritis may cause symptoms of anemia, such as fatigue and weakness, because of decreased production of intrinsic factor (a protein that binds vitamin B12, allowing the B12 to be absorbed and used in the production of red blood cells).

In a small percentage of people with atrophic gastritis, the stomach tissue transforms into another type of digestive tract tissue (metaplasia). In an even smaller percentage of people, metaplasia leads to stomach cancer Stomach Cancer A Helicobacter pylori infection is a major risk factor for stomach cancer. Vague abdominal discomfort, weight loss, and weakness are some typical symptoms. Diagnosis includes endoscopy... read more Stomach Cancer .

Diagnosis of Gastritis

  • Upper endoscopy

A doctor suspects gastritis when a person has upper abdominal discomfort, pain, or nausea. Tests usually are not needed. However, if the doctor is uncertain of the diagnosis, or if symptoms do not resolve with treatment, the doctor may do upper endoscopy Endoscopy Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). In addition to examinations, doctors can use endoscopy to do biopsies and give treatment. Endoscopes... read more .

During upper endoscopy, a doctor uses an endoscope (a flexible viewing tube) to examine the stomach and some of the small intestine. If necessary, the doctor can do a biopsy (removal of a tissue sample for examination under a microscope) of the stomach lining.

Treatment of Gastritis

  • Medications that reduce acid production and antacids

  • Sometimes antibiotics that treat H. pylori infection

  • Treatments to stop bleeding

Regardless of the cause of gastritis, symptoms of gastritis can be relieved by taking medications that neutralize or reduce the production of stomach acid and by discontinuing medications that cause symptoms. (See also Medications for the Treatment of Stomach Acid Medications for the Treatment of Stomach Acid Stomach acid plays a role in a number of disorders of the stomach, including peptic ulcer, gastritis, and gastroesophageal reflux disease (GERD). Although the amount of acid present in the stomach... read more .)

Medications for gastritis

For mild symptoms, taking antacids Antacids Stomach acid plays a role in a number of disorders of the stomach, including peptic ulcer, gastritis, and gastroesophageal reflux disease (GERD). Although the amount of acid present in the stomach... read more , which neutralize acid that has already been produced and released in the stomach, is often sufficient. Almost all antacids can be purchased without a doctor's prescription and are available as tablets, soft chews, or liquids.

Antacids include aluminum hydroxide (which can cause constipation), magnesium hydroxide (which can cause diarrhea), and calcium carbonate. Because antacids can interfere with the absorption of many different medications, people who take other medications should consult a pharmacist or talk with their doctor before taking antacids.

Acid-reducing medications include

H2 blockers are usually more effective than antacids in relieving symptoms, and many people find them far more convenient. Doctors most often prescribe proton pump inhibitors for gastritis associated with bleeding. People typically need to take these acid-reducing medications for 8 to 12 weeks.

Erosive gastritis

People with erosive gastritis must avoid taking medications that irritate the stomach lining (such as NSAIDs Nonsteroidal Anti-Inflammatory Drugs Pain relievers (analgesics) are the main drugs used to treat pain. Doctors choose a pain reliever based on the type and duration of pain and on the drug's likely benefits and risks. Most pain... read more ). Proton pump inhibitors or H2 blockers are prescribed to help protect the stomach lining.

Acute stress gastritis

Most people with acute stress gastritis recover fully when the underlying illness, injury, or bleeding is controlled. However, a small percentage of people in intensive care units have heavy bleeding resulting from acute stress gastritis, which can be fatal. Therefore, doctors try to prevent acute stress gastritis after a major illness, major injury, or severe burn. Medications that reduce acid production are commonly given after surgery and to people in intensive care units to prevent acute stress gastritis. These medications are also used to treat any ulcers that form.

For people with heavy bleeding resulting from acute stress gastritis, a wide variety of treatments have been used. Few of these treatments, however, improve the outcome. Bleeding points can be temporarily heat-sealed (cauterized) during an endoscopy, but bleeding may start again if the underlying illness persists. If bleeding continues, part of the stomach may have to be removed as a lifesaving measure, but this is rarely needed.

Other types of gastritis

There is no cure for postgastrectomy gastritis or atrophic gastritis. People with anemia resulting from decreased absorption of vitamin B12 that occurs with atrophic gastritis must take supplemental injections of the vitamin for the rest of their lives.

Corticosteroids or surgery may be needed to relieve a blocked stomach outlet caused by eosinophilic gastritis.

Removing part or all of the stomach may cure Ménétrier disease. There are no effective medications for Ménétrier disease.

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