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 using 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 for a long time or may lead to a stomach ulcer or cause anaemia.
What causes gastritis?
Your stomach normally produces acid to help with the digestion of food in your digestive tract 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 defence barrier. Gastritis may develop if there is an alteration in this balance, allowing the acid to damage the lining of the stomach.
Infection with H. pylori gastritis
Infection with H. pylori is the cause in about 8 in 10 cases of stomach ulcer. Once you are infected, unless treated, the infection usually stays for the rest of your life. See the separate leaflet called Helicobacter Pylori for more information.
Anti-inflammatory medicines - including aspirin
Anti-inflammatory medicines are sometimes called NSAIDs. Many people take an anti-inflammatory medicine for joint inflammation (arthritis), muscular pains, etc.
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.
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, inflammation of 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).
Symptoms of gastritis may start suddenly and resolve quickly (acute gastritis) or may develop slowly and last for a long period of time (chronic gastritis).
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 gastritis symptoms which may occur include:
- Loss of appetite.
- Feeling sick (nausea).
- Being sick (vomiting).
- You may feel particularly 'full' after a meal.
What else might it be?
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 non-ulcer dyspepsia, duodenal ulcer, stomach ulcer or irritable bowel syndrome. See the separate leaflet called Abdominal Pain.
How to treat gastritis
If you have indigestion and stomach pain, you can try treating this yourself with changes to your diet and lifestyle as follows:
- Eating smaller and more frequent meals.
- Avoiding irritating foods, such as spicy, acidic (for example, fruit juices), fried or fatty foods.
- Not drinking any alcohol.
- Stopping smoking.
- Reducing stress.
You may want to talk with your GP about this - medicines that reduce the amount of acid in your stomach are usually recommended.
- Antacids can be used as a treatment for gastritis to reduce the amount of 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 famotidine) may be used.
- An alternative medicine that may be used is a proton pump inhibitor (PPI) such as lansoprazole or omeprazole.
If your gastritis is caused by Helicobacter pylori (H. pylori)
The tests may show that you have infection with H. pylori. See the separate leaflet called Helicobacter Pylori for more details about the treatment for H. pylori infection.
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.
When to see your doctor about gastritis
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 have recently lost weight without deliberately trying to diet.
- You are finding it difficult to swallow, as if food is getting stuck.
You need to call an emergency ambulance if:
- 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.)
How long does gastritis last?
The length of symptoms can vary depending on the cause and how actively it is managed, either by lifestyle change or medication or a combination of both.
What tests may be done for gastritis?
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. Not everyone with symptoms of gastritis will need to be referred for an endoscopy.
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 stomach 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 stool test (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 for more details.
Having 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.
What are the possible complications of gastritis?
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 bring up (vomit) blood (haematemesis) and you may become anaemic.
Further reading and references
Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management; NICE Clinical Guideline (Sept 2014 - last updated October 2019)
Dyspepsia - proven functional; NICE CKS, July 2023 (UK access only)
Dyspepsia - proven peptic ulcer; NICE CKS, July 2023 (UK access only)
Cellini M, Santaguida MG, Virili C, et al; Hashimoto's Thyroiditis and Autoimmune Gastritis. Front Endocrinol (Lausanne). 2017 Apr 268:92. doi: 10.3389/fendo.2017.00092. eCollection 2017.
Sipponen P, Maaroos HI; Chronic gastritis. Scand J Gastroenterol. 2015 Jun50(6):657-67. doi: 10.3109/00365521.2015.1019918. Epub 2015 Apr 22.