Stomach ulcers are usually caused by infection with a specific bacteria or by irritation from certain pain medicines, not by stress or spicy food.

What is a stomach ulcer?

A stomach ulcer (gastric ulcer) is an open sore in the lining of your stomach that forms when the protective mucus barrier is damaged and acid starts to eat into the tissue.

When this barrier breaks down, the acid and digestive juices cause inflammation, erosion, and eventually an ulcer.

Main causes of ulcers in the stomach

1. Helicobacter pylori (H. pylori) infection

  • H. pylori is a spiral-shaped bacteria that lives in the stomach lining and under the mucus layer.
  • It weakens the protective mucus and triggers inflammation, which allows acid to damage the stomach wall and form an ulcer.
  • This infection is the single most common cause of stomach ulcers worldwide and accounts for a large percentage of duodenal (upper small intestine) ulcers as well.

Think of H. pylori as tiny invaders that hide in the stomach’s mucus coating, quietly irritating it until a sore forms.

2. Long-term use of NSAID painkillers

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, and aspirin can block prostaglandins, which normally help protect the stomach lining.
  • With fewer prostaglandins, the stomach makes less protective mucus and is more exposed to acid, increasing the chance of an ulcer.
  • Regular or high-dose use, older age, and combining NSAIDs with other medicines (like blood thinners or steroids) further raise the risk.

3. Less common medical causes

  • Zollinger–Ellison syndrome: A rare condition where tumors cause the body to produce too much stomach acid, which can overwhelm the protective lining and cause multiple ulcers.
  • Certain serious illnesses or hospital situations: Being critically ill (for example, on a breathing machine) can reduce blood flow to the stomach and weaken its defenses.
  • Other uncommon causes: Some viral infections, chemotherapy or radiation to the stomach area, certain infiltrative diseases, and stomach cancers can present with or lead to ulcers.

Factors that increase the risk (but don’t usually cause ulcers alone)

These don’t typically cause a stomach ulcer by themselves, but they can worsen irritation, slow healing, or make an existing ulcer more likely:

  • Smoking tobacco, which impairs blood flow and healing and adds more damaging chemicals into the stomach environment.
  • Heavy alcohol use, which can irritate and inflame the stomach lining and add to acid-related damage.
  • High stress levels or severe emotional strain, which were once blamed as the main cause but are now seen more as aggravating factors.
  • Spicy or very acidic foods, which may make symptoms (like burning pain) worse but are not considered primary causes of ulcers.

What does not typically cause stomach ulcers

  • Day-to-day stress, on its own, is rarely the root cause; it may just make an existing ulcer feel worse.
  • Spicy foods and acidic foods can trigger discomfort but do not directly create ulcers in a healthy stomach lining.

Many modern clinic and hospital resources now emphasize that infection and medicines are the main culprits rather than stress or diet.

Why knowing the cause matters

  • If H. pylori is the cause, doctors usually prescribe a combination of antibiotics plus acid-suppressing medication to clear the bacteria and allow healing.
  • If NSAIDs are the cause, your provider may reduce the dose, switch you to a different pain medicine, and add stomach-protecting drugs.
  • Addressing risk factors like smoking and heavy alcohol use helps ulcers heal faster and lowers the chance they come back.

If you have persistent burning pain in the upper stomach, black or bloody stools, vomiting blood, or unexplained weight loss, it’s important to see a doctor promptly, as these can be warning signs of an ulcer or a serious complication.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.