What causes stomach ulcer?

Here are some conditions that can cause heartburn, including:

Gastric ulcer (an open wound that appears in the inner lining of the stomach)
Infection with Helicobacter pylori bacteria
Side effects of using nonsteroidal anti-inflammatory drugs (eg ibuprofen and aspirin) and nitrate drugs
Psychological problems (eg anxiety and stress)
Gastroesophageal reflux disease (back movement of stomach acid to the esophagus)
Eat too much
Obesity
Eat too fast
Eating oily, fatty and spicy foods
Smoke
Consuming too much caffeine, soda, or alcoholic beverages
Eat too much chocolate
Constipation

In addition to the above conditions, heartburn can also occur due to complications of a disease. Examples of diseases that can cause stomach ulcers are gallstone disease, pancreatic inflammation (pancreatitis), intestinal ischemia (reduced blood flow in the intestine), intestinal obstruction, celiac disease, hiatus hernia (protruding part of the stomach into the diaphragm), and gastric cancer.