Frequent ulcers almost always trace back to one of a small number of repeating triggers, and about 90% of peptic ulcer cases are linked to just three: a bacterial infection called H. pylori, regular use of anti-inflammatory painkillers like ibuprofen or aspirin, and smoking. If you keep getting ulcers despite treatment, the most likely explanation is that one of these root causes hasn’t been fully addressed, or that more than one is working against you at the same time.
H. pylori: The Most Common Hidden Cause
H. pylori is a bacterium that burrows into the stomach lining and weakens its protective mucus layer. Many people carry it for years without knowing. Even after a full course of antibiotics clears the infection, the bacterium can come back. In one large study, roughly 1.75% of patients tested positive again within a year, and about 4.6% had a recurrence within three years. Early relapses tend to be the original infection flaring back up, while later ones are usually a brand-new infection picked up from contaminated food, water, or close household contact.
A growing problem is antibiotic resistance. Globally, nearly half of H. pylori strains now resist clarithromycin, one of the most commonly prescribed antibiotics for the infection, and over a third resist metronidazole. Those resistance rates have climbed steadily since the early 2000s. If your first round of treatment didn’t work, your doctor can test which antibiotics the bacterium actually responds to and switch your regimen accordingly. Without that step, you may cycle through treatments that never fully clear the infection, and the ulcers keep returning.
Painkillers That Damage the Stomach Lining
Nonsteroidal anti-inflammatory drugs (ibuprofen, naproxen, aspirin) block the production of compounds that help maintain your stomach’s protective barrier. The risk is dose-dependent and tied to body weight. In one controlled study, 40% of people taking the highest dose of an NSAID developed a gastric ulcer within just seven days. When researchers adjusted for body weight, every single ulcer occurred in people receiving more than a certain threshold per kilogram of body weight, while nobody below that threshold developed one.
If you take NSAIDs regularly for chronic pain, arthritis, or heart protection, this is one of the most likely reasons your ulcers keep coming back. Switching to a lower dose, using a type that’s easier on the stomach, or adding a proton pump inhibitor (PPI) to reduce acid production can all help. Current guidelines recommend long-term PPI protection for anyone who has already had a bleeding ulcer and still needs to take NSAIDs or aspirin. Your doctor should prescribe the lowest effective NSAID dose alongside the PPI rather than simply treating each ulcer as it appears.
Smoking and Alcohol
Smoking does more than irritate your stomach. Compounds in tobacco smoke, including nitrosamines and acetaldehyde, directly damage DNA in the cells lining the stomach and interfere with the body’s ability to repair that damage. Nicotine also stimulates receptors that promote abnormal cell growth and new blood vessel formation in damaged tissue, making it harder for ulcers to heal cleanly.
Alcohol works through a similar chemical pathway. When your body metabolizes ethanol, it produces acetaldehyde, a compound that is genotoxic (meaning it damages DNA), disrupts the stomach’s normal repair processes, and triggers oxidative stress in the lining. Heavy or frequent drinking keeps the stomach in a constant state of chemical injury. If you smoke and drink, those effects compound each other and dramatically slow healing, which is why ulcers can feel like they never fully go away.
Stress and Ulcers: What the Evidence Shows
The old idea that “stress causes ulcers” is partly right and partly wrong. Physiological stress, the kind your body experiences during a serious illness, major surgery, or time in an intensive care unit, is a well-documented cause of stomach ulcers. The mechanism involves reduced blood flow to the stomach lining and a breakdown in the mucosal defenses that normally keep acid from digesting your own tissue.
Everyday psychological stress is a different story. It doesn’t directly bore holes in your stomach lining the way H. pylori or NSAIDs do. But chronic stress can push you toward behaviors that do: reaching for ibuprofen more often, drinking more alcohol, smoking more, eating irregularly, or sleeping poorly. Stress also increases stomach acid production and may slow healing. So while it’s not a primary cause in the clinical sense, it absolutely contributes to the cycle of recurrence if it’s leading you toward the habits that damage your stomach.
When Ulcers Won’t Heal
An ulcer that persists after 8 to 12 weeks of proper medication is classified as refractory. This happens for several reasons: an undetected or resistant H. pylori infection, ongoing NSAID use that the patient may not have disclosed or recognized (some cold medicines and combination painkillers contain hidden NSAIDs), continued smoking, or, less commonly, a condition called Zollinger-Ellison syndrome where the body produces far too much stomach acid. In rare cases, what looks like a non-healing ulcer turns out to be stomach cancer, which is why persistent ulcers typically prompt a biopsy.
If you’ve been treated multiple times and your ulcers keep coming back, it’s worth asking your doctor specifically about H. pylori retesting (ideally with a breath test or stool antigen test rather than a blood test, which can stay positive long after the infection is gone) and reviewing every medication you take, including over-the-counter ones.
Mouth Ulcers Are a Different Problem
If the ulcers you keep getting are in your mouth rather than your stomach, the causes are entirely different. Recurrent mouth ulcers (aphthous stomatitis) are strongly linked to nutritional deficiencies, particularly low vitamin B12, iron, folic acid, and vitamin C. In case reports, otherwise healthy young patients who had mouth ulcers for years turned out to have B12 levels well below the normal range (around 65 pmol/L compared to a normal floor of about 116 pmol/L). Correcting the deficiency resolved the ulcers.
Other common triggers for recurrent mouth ulcers include hormonal changes, food sensitivities (especially to acidic fruits, nuts, and chocolate), minor mouth injuries from braces or sharp teeth, and immune system conditions like celiac disease. A simple blood panel checking B12, iron, and folate is a reasonable first step if you’re getting mouth ulcers frequently.
Foods That Don’t Actually Cause Ulcers
Spicy food and coffee are commonly blamed, but the evidence doesn’t support them as ulcer causes. A large meta-analysis found no association between coffee drinking and peptic ulcer risk. Spicy and acidic foods can make an existing ulcer hurt more by irritating already-damaged tissue, but they don’t create the damage in the first place. If you’ve been avoiding entire food groups to prevent ulcers without addressing H. pylori, NSAID use, or smoking, you’re likely restricting your diet for no benefit while leaving the real cause untreated.
Breaking the Cycle
The pattern of recurring ulcers almost always means one core problem hasn’t been solved. For most people, the checklist is straightforward: get tested (or retested) for H. pylori with an accurate method, audit every painkiller you use including over-the-counter ones, and honestly assess smoking and alcohol intake. If you need to stay on NSAIDs or aspirin long-term, a daily PPI taken alongside them significantly reduces the chance of another ulcer. If your H. pylori treatment failed once, resistance-guided antibiotic selection for the second attempt has a much higher success rate than simply repeating the same regimen.