14 Common Causes of Stomach Ulcer

2. H. pylori Bacteria

H. pylori is a common type of bacteria that can live in your stomach. Many people carry it for years without knowing it. In some cases, it damages the stomach lining and leads to an ulcer.

You often pick up this bacteria during childhood. It can spread through contact with saliva, vomit, or stool. Contaminated food or water can also pass it from one person to another. Once inside your stomach, the bacteria weakens the protective lining. This allows stomach acid to irritate the tissue underneath, and over time, this irritation can turn into an open sore.

You may not notice symptoms right away. When symptoms appear, you might feel a burning or dull pain in your upper belly. Some people also notice bloating, nausea, or feeling full too quickly during meals.

H. pylori causes a large share of stomach and upper intestine ulcers worldwide. Not everyone with the bacteria develops an ulcer, but your risk rises if you also take pain relievers often or have other stomach irritation.

3. Smoking

Smoking raises your risk of a stomach ulcer by harming the stomach lining. The chemicals in smoke reduce the stomach’s natural defenses, which makes it easier for acid to irritate the tissue and form sores.

When you smoke, your stomach produces more acid and blood flow to the stomach lining drops. Poor blood flow slows healing and makes small injuries worse over time. Smoking also affects how your body handles infection. It increases the chance that a common stomach bacteria will survive and damage the lining.

If you already have an ulcer, smoking can make symptoms last longer. Pain may feel stronger or return more often. Healing takes more time because smoke interferes with repair of the stomach lining.

Smoking can also reduce how well ulcer treatments work. Acid-lowering drugs may not protect the stomach as well in people who smoke, raising the chance that an ulcer will come back after treatment.

4. Alcohol Consumption

Alcohol use can irritate your stomach lining. When you drink, alcohol increases acid levels and weakens the natural barrier that protects your stomach. This makes it easier for sores to form or existing sores to get worse. Heavy or frequent drinking raises your risk more than occasional use. Large amounts over time can slow healing and lead to ongoing pain. Even smaller amounts may trigger symptoms if you already have a sensitive stomach.

Alcohol can also interact with other common ulcer causes. If you use pain relievers from the anti-inflammatory drug class, alcohol adds extra strain on your stomach lining. Together, they increase the chance of bleeding and tissue damage. Alcohol does not usually create ulcers by itself but plays a supporting role by making damage more likely and healing slower. This effect becomes stronger with daily use or binge drinking.

5. Spicy Foods

Spicy foods often get blamed for stomach ulcers. You may notice more pain or burning after eating hot peppers or spicy sauces because spicy foods can irritate an already sensitive stomach lining.

Spicy foods do not usually create ulcers on their own. Ulcers form when stomach acid damages the lining, often due to certain bacteria or frequent use of pain-relief drugs. When you already have an ulcer, spicy foods can make symptoms feel worse.

Capsaicin, the compound that gives peppers their heat, can increase stomach discomfort for some people. You might feel more burning, nausea, or bloating after a spicy meal. Your response to spicy food can vary. Some people tolerate heat well, while others feel pain quickly. This difference depends on your stomach health and how much spice you eat.

Eating spicy foods on an empty stomach can raise the chance of discomfort. Large portions can also increase irritation. Paying attention to how your body reacts helps you spot patterns tied to your symptoms.

6. High Stress Levels

High stress levels can play a role in stomach ulcers, even though stress alone does not usually cause them. When you feel stressed for long periods, your body reacts in ways that can affect your stomach and make existing damage worse or slow healing.

Stress can raise stomach acid and reduce the natural protection of your stomach lining, which makes your stomach more sensitive to irritation. If you already have small sores, stress may help them grow or become painful.

You may notice more symptoms during stressful times, such as burning stomach pain, nausea, bloating, or feeling full too fast. These symptoms can come and go, which may make them harder to link to stress. Long-term stress may affect your immune system, and this makes it harder for your body to control harmful bacteria in the stomach. Over time, this imbalance can raise the risk of ulcer problems.

7. Zollinger-Ellison Syndrome

Zollinger-Ellison syndrome is a rare cause of stomach ulcers. One or more small tumors grow in your pancreas or upper small intestine and make too much of a hormone called gastrin, which tells your stomach to produce acid.

When your stomach makes too much acid, the lining cannot protect itself. This leads to ulcers in the stomach and small intestine. You may develop more than one ulcer, and they may be harder to heal than usual.

You might notice strong belly pain that does not go away. Diarrhea, nausea, and weight loss can also happen. Some people feel burning pain after meals or at night. These symptoms often last even when common ulcer treatments do not help.

Doctors usually find this condition through blood tests and imaging scans. They look for high gastrin levels and signs of tumors. In some cases, these tumors grow slowly and stay in one place. In other cases, they can spread to nearby organs.

8. Excessive Coffee Consumption

Drinking large amounts of coffee can irritate your stomach lining. Coffee increases stomach acid, which can bother sensitive tissue. Over time, this irritation can raise the risk of a stomach ulcer, especially if other risks are present.

Caffeine plays a key role, but coffee can cause problems even without caffeine. Compounds in coffee stimulate acid release and speed up stomach activity, which leads to pain or burning when your stomach is empty.

You may notice symptoms such as discomfort after drinking coffee. These signs can overlap with ulcer symptoms and make them harder to ignore. Coffee can also interact with other ulcer risks. If you use pain-relieving drugs that thin the stomach lining, coffee can add more strain. Smoking and alcohol use can increase this effect. Your body’s response to coffee varies. Some people tolerate moderate amounts with no issues while others feel pain or nausea after just one cup.

9. Genetics

Your genes can affect your risk of a stomach ulcer. Genetics alone rarely cause an ulcer, but they can make your stomach lining more sensitive to damage. You may inherit traits that affect how your stomach makes acid. Higher acid levels can irritate the lining over time, which makes it easier for a sore to form.

Genes can also affect how your body handles infection. Some people have a weaker defense against H. pylori, a common bacteria linked to ulcers. If this bacteria stays in your stomach longer, it can raise your risk.

Family history matters. If close relatives had stomach ulcers, your chances may be higher. This pattern suggests shared genes, shared habits, or both. Your body’s repair system also links to genetics. Some genes control how fast your stomach heals after damage. Slower healing can allow small injuries to turn into ulcers.

10. Radiation Therapy

Radiation therapy can irritate your stomach lining when treatment targets the chest or belly. Nearby tissue can absorb some energy even if the radiation does not aim directly at the stomach, which weakens its natural barrier and makes sores more likely.

You may notice stomach pain, nausea, or a burning feeling after meals during or after treatment because radiation slows cell repair. This makes the lining heal more slowly and allows acid to damage it more easily.

Radiation also reduces blood flow to the stomach, so less oxygen and fewer nutrients reach the tissue. This delay in healing allows small injuries to turn into ulcers. Some people take drugs that reduce immune response or ease treatment side effects, and these drugs can add stress to the stomach lining. Combining these drugs with radiation increases the risk of irritation. Ulcers linked to radiation may develop during treatment or months later, as tissue damage can build up over time.

11. Internal Bleeding

Internal bleeding can result from a stomach ulcer and make the ulcer worse. When an ulcer eats into a blood vessel, blood leaks into your stomach or intestines. This bleeding can happen slowly over time or start suddenly.

You may not notice early bleeding right away, as small amounts of blood can pass through your body without clear pain. Over time, blood loss can weaken your stomach lining and slow healing.

Common signs of internal bleeding from stomach ulcers include dark or black stool and vomit that appears dark or grainy. Ongoing stomach pain may feel sharp or burning. Weakness, dizziness, or extreme tiredness can also occur as blood loss continues.

Bleeding irritates the stomach lining and exposes deeper tissue. This allows acid to reach sensitive areas and enlarge the ulcer. As bleeding continues, your body struggles to repair the injured lining. Internal bleeding also reduces oxygen flow to stomach tissue, slowing cell repair and keeping the ulcer open.

12. Gastrointestinal Obstructions

Gastrointestinal obstructions occur when something blocks the normal flow of food and fluids in your stomach or small intestine. This blockage raises pressure inside your stomach, which can damage the lining and lead to an ulcer.

Scar tissue from past surgery, swelling from long-term irritation, or growths that narrow the passage can cause an obstruction. Hard, undigested food can also get stuck and slow movement through your digestive system.

When a blockage forms, stomach acid stays in one place for too long and can irritate the stomach lining. This irritation makes it easier for sores to form, especially if your stomach already feels sensitive. Common signs of a blockage include ongoing stomach pain, bloating, and feeling full after small meals.

You might also feel nausea or vomit food that does not look digested. These symptoms often come and go, which can delay care. Obstructions also reduce blood flow to parts of your stomach, limiting healing and weakening the lining.

13. Age

As you get older, your risk of a stomach ulcer rises because your stomach lining becomes thinner over time, which makes it easier for acid to cause damage. You may also produce less protective mucus with age, so small injuries can turn into open sores. Age often brings long-term health issues, and frequent use of anti-inflammatory painkillers can weaken the stomach lining and raise ulcer risk.

Your body heals more slowly with age, so small wounds in the stomach can take longer to close. Older adults often have a higher chance of infection that affects the stomach, which can damage the lining and lead to ulcers. The effects may last longer when treatment starts late.

You might not notice early warning signs as clearly, as pain can feel mild or seem like normal indigestion. This can delay care and allow the ulcer to grow. Age does not cause an ulcer by itself, but increases how strongly other risks affect you, and longer exposure to acid, infections, and certain medicines adds up over time.

14. Type O Blood

Your blood type can influence how your stomach responds to certain bacteria. People with Type O blood have a higher chance of developing stomach ulcers than those with other blood types. However, blood type alone does not cause ulcers.

A common stomach bacteria called H. pylori plays a key role. This germ can damage the stomach lining and lead to sores. Researchers found that H. pylori attaches more easily to the stomach lining in people with Type O blood.

When this bacteria sticks well, it can cause more swelling and irritation. Over time, that damage can turn into an ulcer. Type O blood also affects how your body controls stomach acid. Higher acid levels can irritate the stomach lining, which makes it harder for the stomach to protect itself from damage. Other factors like long-term use of pain relievers, smoking, or stress can also raise the risk. When these combine with Type O blood, ulcers become more likely.