For decades, doctors and patients blamed stomach ulcers on stress, spicy food, and too much acid. Then in 1984, an Australian doctor named Barry Marshall drank a petri dish full of bacteria, deliberately gave himself a stomach ulcer, and then cured it with antibiotics — proving that the real cause of most ulcers was a germ, not a lifestyle. He won the Nobel Prize for Medicine in 2005. Here is what we now know about gastric ulcers — and what you can do about them.
What is a Gastric Ulcer?
Your stomach produces hydrochloric acid — a powerful acid strong enough to dissolve metal. Normally, the stomach lining is protected from this acid by a thick layer of mucus produced by specialised cells. This mucus barrier keeps the acid from touching and burning the stomach wall itself.
A gastric ulcer is a sore — an open wound — that forms on the lining of the stomach when this protective mucus layer is damaged or depleted. The acid reaches the unprotected lining and literally burns a hole through it.
A related condition called a duodenal ulcer occurs just below the stomach, in the first part of the small intestine (the duodenum). Together, gastric and duodenal ulcers are called peptic ulcers. They have the same causes and treatments.
The Real Cause — H. pylori
About 70–80% of gastric ulcers are caused by a bacterium called Helicobacter pylori (H. pylori). This is one of the most remarkable organisms in nature — it has evolved specifically to survive in the highly acidic environment of the stomach, where virtually nothing else can live.
H. pylori survives by:
- Producing an enzyme called urease that converts urea into ammonia, which neutralises the acid immediately around it
- Burrowing into the mucus layer of the stomach lining where acid levels are lower
- Triggering inflammation that gradually destroys the mucus-producing cells
Over months or years, this inflammation weakens the stomach's defences until acid breaks through. The result is an ulcer.
H. pylori is transmitted through contaminated food, water, and close contact — making it extremely common in areas with limited access to clean water. Studies estimate that over 70% of adults in sub-Saharan Africa are infected with H. pylori, though most never develop ulcers.
In 1984, Dr Barry Marshall and his colleague Dr Robin Warren had strong evidence that H. pylori caused ulcers — but the medical establishment would not believe them. Ulcers were believed to be caused by stress and acid. To prove his point, Marshall drank a solution containing millions of H. pylori bacteria. Within days he developed gastritis (stomach inflammation). He then cured himself with antibiotics. This remains one of the most dramatic self-experiments in medical history. The Nobel Committee agreed — they won the prize in 2005.
The Second Major Cause — NSAIDs
Painkiller-Induced Ulcers
The second most common cause of gastric ulcers is regular use of a class of painkillers called NSAIDs — Non-Steroidal Anti-Inflammatory Drugs. These include ibuprofen (Brufen), aspirin, naproxen, diclofenac, and piroxicam.
NSAIDs reduce pain and inflammation by blocking enzymes called COX-1 and COX-2. The problem: COX-1 also produces the prostaglandins that maintain the stomach's mucus protective layer. Block COX-1 and you reduce the stomach's defences — leaving the lining vulnerable to acid.
Risk is highest with:
- Regular or high-dose NSAID use (daily use for pain conditions like arthritis)
- Age over 60 — the stomach lining becomes thinner and more vulnerable with age
- Taking NSAIDs together with corticosteroids (e.g., prednisolone)
- History of previous ulcers
- Taking NSAIDs alongside blood-thinning medications (e.g., warfarin, aspirin)
If you need to take NSAIDs regularly, your doctor can prescribe a stomach-protecting medication called a proton pump inhibitor (PPI) — such as omeprazole — to be taken alongside them.
Symptoms
Common Symptoms
- Burning or gnawing pain in the upper abdomen — the most characteristic symptom. Often described as a dull ache or burning between the belly button and breastbone.
- Pain that is worse when the stomach is empty — typically 2 to 3 hours after eating, or in the middle of the night. This is why many people associate ulcers with hunger — the empty stomach allows acid to sit directly on the ulcer.
- Temporary relief after eating — food buffers the acid, providing brief relief. This relief returning then worsening is a characteristic pattern.
- Nausea
- Bloating and belching
- Loss of appetite — sometimes people avoid eating because they fear the pain that follows
- Unexplained weight loss
Some ulcers cause no symptoms at all — they are discovered only when a complication develops.
Complications — Seek Emergency Care Immediately
- Bleeding ulcer — vomiting blood (which may look like coffee grounds) or passing black, tarry stools (called melaena). This is a medical emergency. Black stools mean digested blood — the ulcer has eroded a blood vessel.
- Perforated ulcer — the ulcer burns completely through the stomach wall, spilling contents into the abdominal cavity. Causes sudden, severe, constant pain across the entire abdomen. Requires emergency surgery.
- Gastric outlet obstruction — swelling from a chronic ulcer blocks the exit from the stomach. Causes persistent vomiting, especially of undigested food.
Diagnosis
- Endoscopy (gastroscopy) — a thin flexible tube with a camera is passed through the mouth into the stomach. Allows direct visualisation of the ulcer and biopsy to test for H. pylori and rule out cancer. The gold standard investigation.
- Urea breath test — the patient drinks a solution containing urea. If H. pylori is present, its urease enzyme breaks down the urea and produces CO2 that is detected in the breath. Non-invasive and highly accurate.
- H. pylori stool antigen test — detects H. pylori proteins in stool. Simple, accurate, and widely available.
- Blood antibody test — detects antibodies to H. pylori but cannot distinguish between current and past infection — less useful for diagnosis.
Treatment
For H. pylori-Positive Ulcers — Triple Therapy
The standard treatment is a combination of three drugs taken simultaneously for 7 to 14 days:
- Proton pump inhibitor (PPI) — omeprazole or lansoprazole — reduces acid production dramatically, allowing the ulcer to heal
- Two antibiotics — typically clarithromycin plus amoxicillin (or metronidazole for penicillin-allergic patients) — to kill the H. pylori bacteria
It is critical to complete the full course even if symptoms improve quickly. Incomplete treatment leads to antibiotic-resistant H. pylori — much harder to treat the second time around.
After treatment, eradication is confirmed with a urea breath test or stool antigen test. Cure rates with triple therapy exceed 85%.
For NSAID-Induced Ulcers
- Stop the offending NSAID if possible
- Take a PPI (omeprazole) for 4 to 8 weeks to allow healing
- If the NSAID cannot be stopped (e.g., for arthritis), continue PPI alongside it indefinitely
- Consider alternative pain relief — paracetamol is safer for the stomach than NSAIDs
Lifestyle Measures That Support Healing
- Quit smoking — smoking impairs mucus production and reduces blood flow to the stomach lining, significantly delaying ulcer healing
- Reduce alcohol — alcohol directly irritates the stomach lining and increases acid production
- Eat regularly — while hunger does not cause ulcers, an empty stomach allows acid to sit on the ulcer and worsen pain
- Avoid foods that trigger your symptoms — spicy food does not cause ulcers but can irritate an existing one; keep a food diary to identify personal triggers
- Manage stress — stress does not cause ulcers but can increase acid production and worsen symptoms
Gastric ulcers used to be considered a chronic, recurring condition that people simply managed for life. Since the discovery of H. pylori, most ulcers can be completely cured — a single course of antibiotics can eliminate the infection permanently. If you have persistent upper abdominal pain, do not just take antacids indefinitely. Get tested. A curable infection should not become a lifelong problem.