Almondsbury Surgery

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Gastritis is very common. It occurs when the lining of your stomach becomes swollen (inflamed). Gastritis is usually mild and resolves without any treatment. However, gastritis can cause pain in the upper part of your tummy (abdomen) and may lead to a stomach ulcer.

Some simple changes to your lifestyle and over-the-counter antacid medicines are often all that is required. Other medicines to reduce the acid in your stomach are sometimes needed. Gastritis usually resolves without any problems. However, if not treated properly, gastritis can last a long time or may lead to a stomach ulcer or anaemia.

Food passes down the gullet (oesophagus) into the stomach. The stomach makes acid which is not essential but helps to digest food. After being mixed in the stomach, food passes into the first part of the small intestine (the duodenum). In the duodenum and the rest of the small intestine, food mixes with chemicals called enzymes. The enzymes come from the pancreas and from cells lining the intestine. The enzymes break down (digest) the food which is taken up (absorbed) into the body.


Gastritis means inflammation of the stomach lining. This means that the lining of your stomach becomes swollen and painful. The irritation may be caused by an infection or a chemical reaction, such as a medicine you're taking or drinking too much alcohol (see below).

Gastritis is very common. However, gastritis is often mild and resolves without any treatment. Severe gastritis is much less common.

Your stomach normally produces acid to help with the digestion of food and to kill germs (bacteria). This acid is corrosive, so some cells on the inside lining of the stomach produce a natural mucous barrier. This protects the lining of the stomach and the first part of the small intestine (the duodenum). There is normally a balance between the amount of acid that you make and the mucous defense barrier. Gastritis may develop if there is an alteration in this balance, allowing the acid to damage the lining of the stomach.

Causes of this include the following:

Infection with Helicobacter pylori (H. pylori gastritis)

Infection with H. pylori is the cause in about 8 in 10 cases of stomach ulcer. More than a quarter of people in the UK become infected with H. pylori at some stage in their lives. Once you are infected, unless treated, the infection usually stays for the rest of your life. In many people it causes no problems and a number of these bacteria just live harmlessly in the lining of the stomach and duodenum. However, in some people this bacterium causes an inflammation in the lining of the stomach or duodenum. This causes the defence mucous barrier to be disrupted (and in some cases the amount of acid to be increased) which allows the acid to cause gastritis.

Anti-inflammatory medicines - including aspirin

Anti-inflammatory medicines are sometimes called non-steroidal anti inflammatory drugs (NSAIDs). There are various types and brands - for example, aspirin, ibuprofen, diclofenac, etc. Many people take an anti-inflammatory medicine for joint inflammation (arthritis), muscular pains, etc. Aspirin is also used by many people to protect against blood clots forming. However, these medicines sometimes affect the mucous barrier of the stomach and allow acid to cause an ulcer. About 2 in 10 stomach ulcers are caused by anti-inflammatory medicines.

Other causes

A stressful event - such as a bad injury or critical illness, or major surgery. Exactly why stress and serious illness can lead to gastritis is not known. However, it may be related to decreased blood flow to the stomach.

Less commonly, gastritis can be caused by an autoimmune reaction - when the immune system mistakenly attacks the body's own cells and tissues (in this case, the stomach lining). This may happen if you already have another autoimmune condition, such as Hashimoto's thyroid disease or type 1 diabetes.

Other causes of gastritis include cocaine abuse or drinking too much alcohol. Occasionally viruses, parasites, fungi and bacteria other than H. pylori are the culprits

Many people with gastritis don't have any symptoms. However, gastritis can cause indigestion (dyspepsia). See the separate leaflet called Dyspepsia (Indigestion).

Gastritis may start suddenly (acute) or may develop slowly and last for a long period of time (chronic).

Pain in your upper tummy (abdomen) just below the breastbone (sternum) is the common symptom. It usually comes and goes. It may be eased if you take antacid tablets. Sometimes food makes the pain worse. The pain may also wake you from sleep.

Other symptoms which may occur include loss of appetite, bloating, retching, feeling sick (nausea) and being sick (vomiting). You may feel particularly 'full' after a meal.

Don't assume that stomach pain is always a sign of gastritis - the pain could be caused by a wide range of other things, such as a stomach ulcer or irritable bowel syndrome. See the separate leaflet called Abdominal Pain.

See your GP if:

  • You have bad pain in your tummy (abdomen) or feel unwell.
  • You have pain or any other indigestion symptoms lasting for more than a week.
  • The gastritis starts after taking any medicine (prescription or over-the-counter).
  • You are vomiting blood or the colour of the vomit is like coffee.
  • You have any blood in your stools (faeces). (Bleeding from your stomach may make your stools look black.)
  • You have recently lost weight without deliberately trying to diet.

Your GP can usually make a diagnosis of gastritis by taking a history of your symptoms and an examination of your tummy (abdomen). Mild gastritis does not usually need any tests.

If gastritis doesn't get better quickly or causes severe pain then your GP will arrange tests. Your GP may arrange blood tests, including a test for anaemia, as gastritis occasionally causes some bleeding from your stomach lining.

Gastroscopy (endoscopy) is the test that can confirm gastritis. In this test a doctor looks inside your stomach by passing a thin, flexible telescope down your gullet (oesophagus). They can see any inflammation or if there is any other abnormality, such as a stomach ulcer.

Small samples (biopsies) are usually taken of the stomach lining during endoscopy. These are sent to the laboratory to be looked at under the microscope. This also checks for cancer (which is ruled out in most cases).

A test to detect the H. pylori germ (bacterium) may also be done. H. pylori can be detected in a sample of stools (faeces), or in a 'breath test', or from a blood test, or from a biopsy sample taken during an endoscopy. See the separate leaflet called Helicobacter Pylori and Stomach Pain for more details.

A barium swallow and X-ray is another way to look for changes (such as ulcers) in the stomach lining. It is not as accurate as an endoscopy.

If you have indigestion and stomach pain, you can try treating this yourself with changes to your diet and lifestyle as follows:

If you think the cause of your gastritis is repeated use of NSAIDs, try switching to a different painkiller that isn't in the NSAID class, such as paracetamol. You may want to talk to your GP about this.

Acid-suppressing medication

Antacids can be used to reduce the acid in your stomach and so let the gastritis resolve.

If treatment with antacid medicine is not enough then a medicine called an H2 blocker (such as ranitidine) may be used. H2 blockers work in a different way on the cells that line the stomach, reducing the production of acid.

An alternative medicine that may be used is a proton pump inhibitor (PPI) such as lansoprazole or omeprazole. PPIs are a group (class) of medicines that work on the cells that line the stomach, reducing the production of acid.

If your gastritis is caused by H. pylori

The tests may show that you have infection with H. pylori. A main part of the treatment is then to clear this infection. If this infection is not cleared, the gastritis is likely to return once you stop taking acid-suppressing medication. Two antibiotics are needed to clear H. pylori. In addition, you need to take an acid-suppressing medicine to reduce the acid in the stomach. This is needed to allow the antibiotics to work well. You need to take this 'combination therapy' (sometimes called 'triple therapy') for a week. One course of combination therapy clears H. pylori infection in up to 9 in 10 cases. If H. pylori is cleared, the chance of a stomach ulcer returning is greatly reduced. However, in a small number of people H. pylori infection returns at some stage in the future.

If your gastritis is caused by an anti-inflammatory medicine

If possible, you should stop the anti-inflammatory medicine. This allows the gastritis to heal. You will also normally be prescribed an acid-suppressing medicine for several weeks. This stops the stomach from making acid and allows the gastritis to heal. However, in many cases the anti-inflammatory medicine is needed to ease symptoms of joint inflammation (arthritis) or other painful conditions, or aspirin is needed to protect against blood clots. In these situations, one option is to take an acid-suppressing medicine each day indefinitely. This reduces the amount of acid made by the stomach and greatly reduces the chance of gastritis forming again.

Gastritis usually resolves without any complications. Occasionally gastritis may develop into a stomach ulcer.

Bleeding from the stomach lining may also occur. This may cause you to become anaemic.

For most people, gastritis isn't serious and improves very quickly. The outlook is much worse if there is an underlying cause that isn't treated or changed. For example, continuing to drink too much alcohol or using an NSAID such as ibuprofen will cause gastritis to become worse and not get better.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Dr Colin Tidy
Peer Reviewer:
Dr Hayley Willacy
Document ID:
29136 (v1)
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