Stomach polyps usually don't cause signs or symptoms.

But as a stomach polyp enlarges, open sores (ulcers) can develop on its surface. Rarely, the polyp can block the opening between your stomach and your small intestine.

Signs and symptoms of stomach polyps include:

• Pain or tenderness when you press your abdomen
• Nausea
• Blood in your stool
• Anemia

Stomach polyps form in response to damage to your stomach lining. The most common causes of stomach polyps are:

• Chronic stomach inflammation. Also known as gastritis, this condition can cause the formation of hyperplastic polyps and adenomas. Hyperplastic polyps are unlikely to become cancerous, although those larger than about 2/5 inch (1 centimeter) carry a greater risk. Adenomas are the least common type of stomach polyp but the type most likely to become cancerous. For that reason, they are generally removed.
• Familial adenomatous polyposis. This rare, inherited syndrome causes certain cells on the stomach's inner lining to a specific type of polyps called fundic gland polyps. When associated with this syndrome, fundic gland polyps are removed because they can become cancerous. Familial adenomatous polyposis can also cause adenomas.
• Regular use of certain stomach medications. Fundic gland polyps are common among people who regularly take proton pump inhibitors to reduce stomach acid. These polyps are generally small and aren't a cause for concern. Fundic gland polyps with a diameter larger than about 2/5 inch (1 centimeter) carry a small risk of cancer, so your doctor might recommend discontinuing proton pump inhibitors or removing the polyp or both.

Factors that increase your chances of developing stomach polyps include:

• Age. Stomach polyps are more common among people in midadulthood to late adulthood.
• Bacterial stomach infection. Helicobacter pylori (H. pylori) bacteria are a common cause of the gastritis that contributes to hyperplastic polyps and adenomas.
• Familial adenomatous polyposis. This rare, inherited syndrome increases the risk of colon cancer and other conditions, including stomach polyps.
• Certain medications. Long-term use of proton pump inhibitors, which are medications used to treat gastroesophageal reflux disease, has been linked to fundic gland polyps.