Helicobacter pylori infection

Overview

Helicobacter pylori, usually shortened to H. pylori, is a spiral-shaped bacterium (germ) that lives in the layer of mucus covering the inside of the stomach. It protects itself from stomach acid and hides in the mucus, so the body cannot clear it. Without treatment, the infection usually stays for life.

H. pylori is very common. About two out of every three people in the world carry it, and rates are higher in low- and middle-income countries. Most people pick it up in childhood from other people, through saliva, vomit or stool, or from unclean food and water. Crowded homes and poor sanitation make spread more likely.

Most people with H. pylori never feel unwell. In others, the germ causes long-term inflammation of the stomach lining (gastritis) and can lead to ulcers in the stomach or duodenum (the first part of the small intestine). About one in ten infected people develop an ulcer. Over many years, the infection can also raise the risk of stomach cancer and a rare stomach lymphoma.

The good news is that simple tests can find the infection, and a short course of several medicines taken together usually cures it. Clearing the germ helps ulcers heal, makes them less likely to come back, and lowers the risk of stomach cancer.

Symptoms

• No symptoms at all in most people who carry the germ
• Aching or burning pain in the upper belly, often worse when the stomach is empty
• Feeling hungry or empty one to three hours after a meal
• Bloating or feeling full quickly, so you cannot eat or drink your usual amount
• Nausea (feeling sick) or loss of appetite
• Frequent burping
• Weight loss without trying
• Black, tarry stools or vomiting blood, which are signs of a bleeding ulcer

Causes and risk factors

Causes

• Infection with the Helicobacter pylori bacterium, which settles in the mucus lining of the stomach
• Spread from person to person through contact with saliva, vomit or stool, usually in childhood
• Eating food or drinking water that has been contaminated with the germ
• The germ inflames the stomach lining and upsets the balance of stomach acid, which can lead to gastritis and ulcers

What makes it more likely

• Growing up or living in a low- or middle-income country where the infection is common
• Living in a crowded home
• Poor sanitation or unsafe drinking water
• Living with a family member who has H. pylori
• Low household income
• Childhood, which is when most people catch it

Complications

Long-term infection keeps the stomach lining inflamed. This can cause peptic ulcers (sores in the stomach or duodenum). Ulcers may bleed heavily, make a hole in the stomach or bowel wall (perforation), or leave scars that slow stomach emptying. Slow, hidden bleeding can cause iron deficiency anaemia (low blood). Over many years, ongoing inflammation can thin the stomach lining (atrophic gastritis) and change its cells, which raises the risk of stomach cancer. H. pylori is also linked to gastric MALT lymphoma, a rare cancer of immune cells in the stomach; this often shrinks when the germ is cleared. The World Health Organization's cancer agency lists H. pylori as a cause of cancer in humans.

Diagnosis

H. pylori is found with simple tests. The urea breath test is the most used: you swallow a special drink or tablet and then breathe into a tube, and the germ shows up in your breath. A stool test looks for parts of the germ in a poo sample. A blood antibody test is less useful because it stays positive after the germ has gone, so it cannot tell old infection from current infection, and it cannot show whether treatment worked. Acid-lowering medicines (proton pump inhibitors) can hide the germ, so they are usually stopped for two weeks before a breath or stool test, and antibiotics and bismuth for four weeks. Your doctor will guide you on this.

An endoscopy (a thin, flexible camera passed through the mouth into the stomach) with small tissue samples (biopsies) is used for older people and for anyone with warning signs such as bleeding, vomiting, weight loss or anaemia. Biopsies can also show which antibiotics will work. After treatment, a breath or stool test done at least four weeks later checks that the germ has gone.

Treatment

1. Confirm the infection with a breath, stool or biopsy test before treatment. Guidelines advise treating everyone who tests positive.
2. Tell your doctor about every antibiotic you have taken before (especially clarithromycin, metronidazole or levofloxacin) and about any penicillin allergy, because this guides the choice of medicines.
3. Your doctor prescribes a combination treatment: an acid-lowering medicine (usually a proton pump inhibitor) together with two or three other medicines, such as antibiotics and sometimes bismuth, usually for 10 to 14 days. Your doctor decides the medicines, the dose and the length of the course.
4. Where many germs resist clarithromycin, or resistance is unknown, guidelines prefer bismuth quadruple therapy (an acid-lowering medicine, bismuth, tetracycline and metronidazole) as the first treatment.
5. Take every dose and finish the whole course, even if you feel better. Missing doses is a common reason treatment fails.
6. Have a repeat breath or stool test at least four weeks after finishing treatment to check the germ has gone.
7. If the germ is still there, the doctor chooses a different combination that avoids antibiotics used before, and may arrange a specialist review or a test to see which antibiotics will work.

Medicines in Pakistan

Medicines a doctor may use, by group. Each link opens our page for that medicine, with every brand and its official DRAP price. Your doctor decides which medicine and dose are right for you.

Also used (not yet in our price list): Bismuth salts (part of bismuth quadruple therapy), Rifabutin (used in a later-line combination when earlier treatment has failed), Vonoprazan (a potassium-competitive acid blocker used in some newer combinations), Lansoprazole, pantoprazole and rabeprazole (other proton pump inhibitors)

Self-care and prevention

Self-care

• Take every dose of your treatment and finish the full course, even if you feel better
• If side effects bother you, speak to your doctor or pharmacist rather than stopping on your own
• Keep a note of the antibiotics you have taken in the past and share it with your doctor
• Avoid anti-inflammatory painkillers (NSAIDs) such as ibuprofen unless your doctor says they are needed
• Before a breath or stool test, ask your doctor whether to stop your acid medicine; an antacid can ease symptoms in the meantime
• Go back for the repeat test after treatment to make sure the germ has gone
• Wash your hands with soap after using the toilet and before preparing or eating food

Prevention

• Wash hands with soap after using the toilet and before handling food
• Drink safe, clean water and eat food that has been prepared hygienically
• Adults who live with someone who has H. pylori may be advised to get tested too
• Finish treatment fully and have the repeat test, because the germ can return where sanitation is poor

Common questions

Is H. pylori contagious?

Yes. It passes from person to person, most often in childhood, through saliva, vomit or stool, and possibly through unclean food or water. This is why it often runs in families. Adults who live with an infected person may be advised to get tested.

Can H. pylori go away without treatment?

Usually not. Once a person has it, the infection tends to last for life unless it is treated with the right combination of medicines. Many people never have symptoms, but the germ can still cause ulcers or raise cancer risk over time.

Why do I need so many medicines at once?

The germ is hard to kill and can become resistant to single antibiotics. Using an acid-lowering medicine together with two or three other medicines gives the best chance of a cure. Your doctor chooses the combination based on your past antibiotic use, any allergies and local resistance.

Does H. pylori cause stomach cancer?

It is the most important known risk factor for stomach cancer, but most people who carry it never get cancer. Clearing the infection lowers the risk. People with a family history of stomach cancer should tell their doctor.

Why can't I use a blood test to check if treatment worked?

Antibodies in the blood stay for a long time after the germ has gone, so a blood test cannot tell old infection from current infection. A breath test or stool test, done at least four weeks after treatment, is used to confirm a cure.

Sources

1. NICE. Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management (CG184) - Recommendations (2019).
2. American College of Gastroenterology. Treatment of Helicobacter pylori Infection (ACG Guideline Highlights) (2024).
3. European Helicobacter and Microbiota Study Group (Gut, BMJ). Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report (2022).
4. MedlinePlus. Helicobacter pylori infection: MedlinePlus Medical Encyclopedia (2026).
5. NHS. Stomach ulcer - NHS (accessed 2026).
6. National Cancer Institute (NIH). Helicobacter pylori (H. pylori) and Cancer (2023).
7. Infection and Drug Resistance (Dove Medical Press). Characterization of Domain V Mutations in Clinical Isolates of Helicobacter pylori in Pakistan and Their Effect on Clarithromycin MIC (2021).

Prepared from the sources listed below by the MedInfoBase team. Last reviewed 16 October 2026. This page is general health information, not medical advice. It gives no doses and does not replace a doctor: talk to your doctor or pharmacist before starting, stopping or changing any medicine. How we write and check our pages.

Related conditions

Peptic ulcer diseaseGastro-oesophageal reflux disease (GERD)Iron-deficiency anaemia

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