Learn About Stomach Ulcers And Their Causes

What Are Stomach Ulcers and How Do They Form

A stomach ulcer is an open sore that develops on the lining of the stomach. Think of it like a cut on your skin, but instead of being on the outside of your body, it forms on the inside wall of your stomach. The stomach naturally produces strong acid to help break down food during digestion. Normally, a protective layer of mucus shields the stomach lining from this acid. When that protective layer breaks down or becomes damaged, the acid eats away at the stomach tissue underneath, creating an ulcer.

Stomach ulcers are also called gastric ulcers or peptic ulcers (peptic ulcers can form in the stomach or small intestine). The process of ulcer formation happens gradually. First, the protective mucus layer thins or develops a weak spot. Then, stomach acid reaches the sensitive tissue below. Over time, this acid exposure creates a small hole or crater in the stomach lining. Some ulcers are tiny, while others can grow larger and cause serious problems. According to medical data, stomach ulcers affect roughly 1 in 20 people at some point in their lives.

The symptoms of stomach ulcers vary from person to person. Some people experience burning stomach pain, especially between meals or at night. Others feel bloating, heartburn, or nausea. In more severe cases, ulcers can cause vomiting (sometimes with blood), dark or bloody stools, unexplained weight loss, and loss of appetite. Not everyone with an ulcer notices symptoms right away, which is why some ulcers go undetected until they cause complications.

Understanding what happens inside your stomach helps explain why ulcers develop and why certain factors make them more likely. The stomach lining contains millions of cells that produce both acid and protective mucus. These two substances normally balance each other. When that balance shifts, ulcers can form. This is why learning about ulcer causes matters so much—identifying what disrupted that balance is the first step toward preventing future ulcers or managing existing ones.

Practical Takeaway: Stomach ulcers are open sores on the stomach lining caused by damage to the protective mucus layer. Symptoms can range from mild to severe, and some people have no symptoms at all. If you experience persistent stomach pain, burning sensations, or digestive changes, speaking with a healthcare provider can help identify what's happening inside your stomach.

Helicobacter Pylori: A Major Cause of Stomach Ulcers

Helicobacter pylori, often called H. pylori, is a bacterium that lives in the stomach and is responsible for causing roughly 60% to 90% of all stomach ulcers worldwide. This bacterium is particularly common in developing countries but also occurs in developed nations. H. pylori causes ulcers by damaging the protective mucus layer and triggering inflammation in the stomach lining, which weakens its ability to resist acid.

The bacterium has special adaptations that allow it to survive in the harsh, acidic environment of the stomach. It produces an enzyme that neutralizes stomach acid in its immediate vicinity, creating a safe space where it can live and reproduce. H. pylori also has whip-like structures called flagella that help it move through the thick mucus layer to find protected spots. Once established, the bacteria release substances that trigger the stomach's immune system to attack, causing additional inflammation and damage to the lining.

People typically catch H. pylori through contaminated food or water, or through close contact with an infected person. Sharing eating utensils, toothbrushes, or kissing can spread the bacteria. In many cases, people get infected during childhood, often in areas with poor sanitation or crowded living conditions. The infection can remain in the stomach for years or even a lifetime if left untreated. Many people carry H. pylori without ever developing an ulcer, but others do develop ulcers years after initial infection.

Diagnosing H. pylori infection involves several possible tests. A breath test is common—the patient swallows a substance containing a harmless radioactive isotope, and if H. pylori is present, it breaks down the substance and the patient exhales a detectable gas. Blood tests can also detect antibodies to H. pylori. Stool tests and endoscopy with biopsies (where a tiny tissue sample is taken from the stomach) are other diagnostic methods. Once H. pylori is confirmed, doctors typically prescribe a combination of antibiotics and acid-reducing medications to eliminate the infection and allow the ulcer to heal.

Practical Takeaway: H. pylori is a bacterium responsible for the majority of stomach ulcers. It spreads through contaminated food, water, or close personal contact. Testing for H. pylori is straightforward, and treating the infection with antibiotics can prevent ulcers from developing or returning. If you have a family history of stomach ulcers or ulcer-related problems, discussing H. pylori testing with your healthcare provider may be worthwhile.

Nonsteroidal Anti-Inflammatory Drugs and Ulcer Risk

Nonsteroidal anti-inflammatory drugs (NSAIDs) are the second most common cause of stomach ulcers, responsible for about 15% to 25% of ulcer cases. NSAIDs are medications people use regularly to reduce pain and inflammation. Common over-the-counter NSAIDs include ibuprofen (Advil, Motrin), naproxen (Aleve), and aspirin. Prescription NSAIDs include indomethacin, meloxicam, and others. Many people take these medications without thinking much about the risks, especially since they're available without a prescription at pharmacies and grocery stores.

NSAIDs damage the stomach lining through a specific mechanism: they block an enzyme called cyclooxygenase (COX), which produces protective prostaglandins. These prostaglandins normally maintain the mucus layer and blood flow to the stomach lining. Without adequate prostaglandins, the protective layer weakens and becomes vulnerable to stomach acid. Interestingly, the damage can occur even at recommended doses in some people. Regular NSAID use carries higher risk than occasional use, which is why people taking these medications daily—especially for chronic pain conditions—face greater ulcer risk.

Certain groups face higher risk when taking NSAIDs. People over 65 years old have significantly higher ulcer risk from NSAIDs than younger adults. Those with a history of stomach ulcers are at increased risk if they resume NSAID use. People who take NSAIDs while also infected with H. pylori have a compounded risk—the combination is particularly dangerous. Additionally, taking NSAIDs with corticosteroids or blood-thinning medications increases ulcer risk. Heavy alcohol use combined with NSAID use also raises the danger.

People who need NSAIDs regularly have options to reduce ulcer risk. Taking the lowest effective dose for the shortest time necessary helps. Taking NSAIDs with food can offer some protection. For people at high risk, doctors may prescribe additional medications that reduce stomach acid (proton pump inhibitors or H2 blockers) to use alongside NSAIDs. Some people can switch to acetaminophen or other pain management strategies. Healthcare providers can discuss which approach makes sense based on individual health history and reasons for taking the medication.

Practical Takeaway: NSAIDs are common pain relievers that can damage the stomach lining and cause ulcers, especially with regular use. If you take NSAIDs frequently, discuss your risk factors with a healthcare provider. They can recommend protective strategies, such as taking the medication with food, using the lowest effective dose, or adding protective medications if needed.

Other Causes and Contributing Factors

While H. pylori and NSAIDs account for the vast majority of stomach ulcers, several other factors can contribute to ulcer development. These less common causes explain some cases and may combine with major causes to increase risk. Stress is often blamed for ulcers, though the relationship is more complex than once thought. Severe physical stress from surgery, burns, head injuries, or critical illness can trigger "stress ulcers," which form rapidly in the stomach of hospitalized patients. However, everyday emotional stress doesn't directly cause ulcers in most people—it's more likely to worsen existing conditions or increase acid production in susceptible individuals.

Alcohol consumption, particularly heavy drinking, irritates the stomach lining and can weaken the protective mucus layer. While