H. pylori Infection

Understanding the bacterium that causes ulcers and stomach problems

Last reviewed: February 2026

Helicobacter pylori Spiral bacteria with flagella living in stomach mucus Stomach lining Mucus layer

🦠 What is H. pylori?

Helicobacter pylori (H. pylori) is a spiral-shaped bacterium that lives in the stomach lining of approximately half the world's population. It's uniquely adapted to survive the stomach's harsh acidic environment by producing an enzyme called urease, which neutralizes stomach acid in its immediate vicinity.

H. pylori infection is the most common chronic bacterial infection in humans. While most infected people never develop symptoms, H. pylori is the primary cause of peptic ulcers and gastritis, and it's classified as a Group 1 carcinogen due to its link to stomach cancer.

🌍
50%
World population infected
👶
Childhood
Most infections acquired early
🤷
80%+
Have no symptoms
💊
Curable
With antibiotics + PPIs

🔄 How H. pylori Spreads

H. pylori is typically acquired in childhood and persists lifelong without treatment. Transmission routes include:

Routes of Transmission

Risk Factors for Infection

Factor Why It Increases Risk
Living in developing countries Higher rates due to crowding, sanitation issues
Crowded living conditions More opportunities for person-to-person spread
Lack of clean water Waterborne transmission possible
Living with infected person Family clustering is common
Lower socioeconomic status Associated with many of above factors
H. pylori rates have been declining in developed countries due to improved sanitation, smaller family sizes, and antibiotic use. However, it remains very common in developing regions.

🔍 Symptoms and Related Conditions

Most people with H. pylori have no symptoms. When problems do occur, they're usually related to:

Gastritis

Peptic Ulcers

Other Associated Conditions

Seek medical attention if you have:
  • Persistent stomach pain
  • Difficulty swallowing
  • Vomiting blood or material like coffee grounds
  • Black, tarry stools
  • Unexplained weight loss

🩺 Testing for H. pylori

Non-Invasive Tests

Test How It Works Accuracy Notes
Urea Breath Test (UBT) Drink urea solution; H. pylori breaks it down, releasing CO2 you breathe out >95% Gold standard non-invasive test; stop PPIs 2 weeks before
Stool Antigen Test Detects H. pylori proteins in stool >90% Good for diagnosis and confirming eradication
Blood Antibody Test Detects antibodies against H. pylori 85% Can't distinguish current from past infection; not for confirming eradication

Invasive Tests (During Endoscopy)

Important Testing Considerations

  • Stop PPIs: At least 2 weeks before breath or stool tests (can cause false negatives)
  • Stop antibiotics: At least 4 weeks before testing
  • H2 blockers: Can usually continue, but some recommend stopping 24-48 hours before
  • Antacids: Generally don't affect results

💊 Treatment

H. pylori treatment requires combination therapy because single antibiotics are ineffective. Typical regimens include:

First-Line Treatment Options

Triple Therapy (14 days)

Bismuth Quadruple Therapy (10-14 days)

Concomitant Therapy (14 days)

Treatment Tips

Common Side Effects

Treatment success rates have declined due to antibiotic resistance, especially to clarithromycin. If first-line treatment fails, a different regimen will be used for second-line therapy.

✅ After Treatment

Confirming Eradication

What If Treatment Fails?

Can You Get Reinfected?

Reinfection after successful treatment is uncommon in adults (about 1-2% per year in developed countries). Factors that help prevent reinfection:

❓ Who Should Be Tested and Treated?

Test and Treat If:

Consider Testing:

Routine testing of asymptomatic individuals is not generally recommended in Western countries. However, in areas with high stomach cancer rates, screening may be considered.

⚠️ Long-term Health Implications

Stomach Cancer Risk

Progression of Infection

Initial Infection
Acute gastritis develops in all infected individuals
Chronic Gastritis
Persists in most; may cause no symptoms
Peptic Ulcer (10-15%)
Develops in a minority over years/decades
Atrophic Gastritis (Some)
Stomach lining thins; precursor to cancer
Intestinal Metaplasia (Few)
Cells change type; further cancer risk
Stomach Cancer (<1%)
Rare outcome after decades of infection

❓ Frequently Asked Questions

Should I get treated if I have H. pylori but no symptoms?
This is debated. In countries with high stomach cancer rates, treating even asymptomatic infection may be beneficial. In low-risk areas, the decision depends on individual factors. Discuss with your doctor—considerations include family history of stomach cancer, your comfort level with lifelong infection, and potential medication side effects.
Is H. pylori contagious?
Yes, H. pylori can spread from person to person, usually through saliva, contaminated food, or water. It's most commonly transmitted in childhood within families. Adults rarely acquire new infections. Close family members of infected individuals have higher infection rates.
Should my family be tested?
If you have an active ulcer or have had ulcer complications, testing family members may be reasonable since reinfection from untreated contacts is possible. For uncomplicated infection, routine family testing isn't typically recommended unless family members have their own symptoms.
Can probiotics help with H. pylori?
Probiotics don't eradicate H. pylori on their own, but some studies suggest they may help in two ways: 1) Reducing side effects of antibiotic treatment, and 2) Possibly modestly improving eradication rates when added to standard therapy. They're sometimes recommended as an adjunct to treatment but shouldn't replace antibiotics.
How did I get H. pylori if I eat clean food?
Most people acquire H. pylori in childhood, often before age 10, usually from close family contacts. You may have been infected decades ago in conditions different from your current lifestyle. The infection persists lifelong without treatment, regardless of current diet or hygiene practices.