Definition of Gastritis:

Gastritis is an inflammation (irritation and swelling) of the lining of the stomach.

Causes, incidence, and risk factors:

There are many causes of gastritis.

The most common are:

• Alcohol
• Erosion (loss) of the protective layer of the stomach lining
• Infection of the stomach with Helicobacter pylori bacteria
• Medications such as aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs)
• Smoking

Less common causes are:

• Autoimmune disorders (such as pernicious anemia)
• Backflow of bile into the stomach (bile reflux)
• Eating or drinking caustic or corrosive substances (such as poisons)
• Excess gastric acid secretion (such as from stress)
• Viral infection, especially in people with a weak immune system

Gastritis can last a short time (acute gastritis) or for months to years (chronic gastritis).