There are many things that can increase the risk of gastritis. The most common causes follow:

• Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen and naproxen. NSAIDs are commonly used for pain relief, but they can also increase acidic gastric juices produced in the stomach. The increased stomach acid can inflame and wear down the stomach lining.
• Infection with bacteria called Helicobacter pylori (H. pylori). These bacteria are found in about a third of Australian adults. Even so, many of those infected with H. pylori don’t develop any gastritis symptoms or ulcers. The reason for this is not clear.
• Drinking alcohol excessively. Excessive drinking can erode the lining of the stomach, making it weaker and more likely to be damaged by the stomach’s acidic digestive juices.

Other causes of gastritis include:

• autoimmune gastritis – this is when your own body attacks the cells in your stomach and wears down your stomach lining
• extreme stress to the stomach – such as from major surgery, injury, burns or severe infections
• backflow of bile into the stomach (known as ‘bile reflux’).
• infection caused by viruses (for example, cytomegalovirus), especially in people who already have a weakened immune system (such as in AIDS)
• diseases such as Crohn’s disease
• infections caused by some fungus, bacteria, viruses and parasites.

See your doctor if you suspect you have gastritis – and especially if you have any of the following:

• gastritis symptoms that last more than a week
• vomiting blood or black, tarry substance (dried blood)
• blood in your stool (poo), or stool that is black.

If left untreated, gastritis can lead to stomach ulcers and bleeding. While rare, it can also increase the risk of stomach cancer.