Causes

Most peptic ulcers are associated with a spiral-shaped bacterium called Helicobacter pylori. The bacterium lives in the acidic environment of the stomach and it can cause a chronic inflammation there, resulting in a defect in the regulation of a certain hormone (gastrin) production, which stimulates acid secretion. Acid then erodes the inner lining of stomach or duodenum causing ulcer. Ulcers can also be caused by drugs such as nonsteroideal anti-inflammatory drugs (NSAIDs) or aspirin.

Helicobacter pylori (H. pylori)

• It is believed that H. pylori weakens the protective mucous coating of the stomach and duodenum by causing inflammation, so that the stomach acid can cause damage. 
  
  
• H. pylori is a type of bacteria which is found in the stomach of people with and without peptic ulcers.
  
  
• More than 9 out of 10 people with a duodenal ulcer and about 7 out of 10 with a gastric ulcer are infected with H. pylori. 
  
  
• Although H. pylori is present in the stomachs of 20% (1 in 5 people) of people in the USA under the age of 40 years and half of those aged over 60 years, not all these people develop peptic ulcers.
  

Drug use
Certain medicines such as nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin and steroids also increase the risk of peptic ulcers. These drugs reduce the protection of the stomach lining against damage by stomach acid. Among people taking these drugs, the risk of a peptic ulcer occurring is further increased if they are also infected with H. pylori.

Additional factors
Additional factors that may influence the course of the disease include:

• Food and drinks – spicy food, caffeine and alcohol may irritate peptic ulcers. 
  
  
• Smoking may increase the time that an ulcer takes to heal. 
  
  
• Stress – the role of stress in the development of peptic ulcers is still being debated.