In the majority of cases, a bacteria called helicobacter pylori (HP) infects the mucosal lining, causing inflammation which weakens the lining and leads to ulceration.

Another cause is the class of painkillers called NSAIDs (non-steroidal antiinflammatory drugs) which affects the action of prostaglandins, a protective substance produced by the mucosa. Many painkillers (apart from paracetamol, codeine and tramadol) belong to this group. Examples include diclofenac, naproxen, ketoprofen, indomethacin and celecoxib. Check with your doctor if your painkillers are NSAIDS. Aspirin used for heart and stroke patients is also in this group. Doctors often prescribe an antiulcer drug when prescribing these medications. With the exception of aspirin, NSAIDs should not be taken continuously.