What causes stomach ulcers?
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 and the first part of the gut (small intestine) known as the duodenum produce a natural mucous barrier. This protects the lining of the stomach and duodenum.
There is normally a balance between the amount of acid that you make and the mucous defence barrier. An ulcer may develop if there is an alteration in this balance, allowing the acid to damage the lining of the stomach or duodenum. Causes of this include the following:
Infection with Helicobacter pylori
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 of 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 inflammation and ulcers.
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 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 and factors
Other causes are rare. For example, some viral infections can cause a stomach ulcer. Crohn's disease may cause a stomach ulcer in addition to other problems of the gut.
Stomach cancer may at first look similar to an ulcer. Stomach cancer is uncommon but may need to be 'ruled out' if you are found to have a stomach ulcer.
Did you find this information useful?
- Dyspepsia and gastro‑oesophageal reflux disease: Investigation and management of dyspepsia - symptoms suggestive of gastro‑oesophageal reflux disease - or both; NICE Clinical Guideline (Sept 2014)
- Dyspepsia - proven peptic ulcer; NICE CKS, July 2015 (UK access only)
- Cai S, Garcia Rodriguez LA, Masso-Gonzalez EL, et al; Uncomplicated peptic ulcer in the UK: trends from 1997 to 2005. Aliment Pharmacol Ther. 2009 Nov 15 30(10):1039-48. Epub 2009 Aug 26.
- Sachs G, Scott DR, Wen Y; Gastric infection by Helicobacter pylori. Curr Gastroenterol Rep. 2011 Dec 13(6):540-6. doi: 10.1007/s11894-011-0226-4.
- Niv Y; H. pylori/NSAID--negative peptic ulcer - the mucin theory. Med Hypotheses. 2010 Nov 75(5):433-5. Epub 2010 May 4.
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