Helicobacter pylori is a bacterium that can persist in the stomach lining. Infection may cause no symptoms, upper-abdominal discomfort, indigestion or peptic ulcer disease. It is also an important gastric-cancer risk factor, but infection does not mean that cancer is already present.
The practical priorities are choosing the right test, completing clinician-directed treatment after a positive result, and confirming eradication at the appropriate time. Improvement in pain or bloating alone cannot show whether the bacterium remains.
Key points: H. pylori can be present without stomach pain. Urea breath and stool antigen tests detect active infection and are commonly used after treatment. Blood antibodies may stay positive after eradication and usually cannot confirm cure. Take a positive report back for assessment, complete treatment and attend the advised test of cure.
What is H. pylori and does infection always cause symptoms?
H. pylori survives in the acidic stomach environment and can cause long-standing inflammation of the lining. Many infected people have no specific symptoms, so feeling well does not exclude infection, and every episode of bloating, nausea or upper-abdominal pain should not automatically be blamed on it.
Infection is associated with chronic gastritis, stomach or duodenal ulcers, selected stomach lymphoid disorders and gastric-cancer risk. Whether lining damage is present depends on age, symptoms, family history, medicine history and examination results. A positive test warrants medical assessment; it does not prove ulcer or cancer.
Who should discuss H. pylori testing with a clinician?
People with recurrent upper-abdominal pain, post-meal fullness, nausea or indigestion can ask whether testing is appropriate. A history of peptic ulcer, stomach-lining changes, a first-degree relative with gastric cancer, unexplained iron-deficiency anaemia, or an infected household member may also be relevant.
From 2026, Taiwan provides one publicly funded stool antigen test in a lifetime for eligible people aged 45–74. Eligibility, participating facilities and updates follow the Health Promotion Administration announcement. Symptoms or warning signs require clinical assessment rather than waiting for screening.
- Recurrent upper-abdominal pain, bloating, nausea or indigestion
- Previous stomach or duodenal ulcer
- A first-degree relative with gastric cancer or clinician-assessed higher risk
- Previous H. pylori treatment without a test of cure
- Current eligibility for the public programme without prior use
How do breath, stool and endoscopic tests differ?
Tests are either non-invasive or based on samples taken during endoscopy. The choice depends on warning signs, whether the stomach lining must be seen directly, recent medicines and whether this is a post-treatment check. The tests answer different questions, so convenience alone should not determine the choice.
| Test | What it can show | Typical use and limitation |
|---|---|---|
| Urea breath test | Current active infection | Non-invasive and often used after treatment; some medicines interfere |
| Stool antigen test | Current active infection | Useful for screening and follow-up; collection and storage instructions matter |
| Endoscopic sample | Bacteria plus direct assessment of the stomach lining | Valuable with warning signs, ulcer risk or a lesion requiring assessment |
| Blood antibody test | Immune response to past or current exposure | May remain positive after eradication and usually cannot confirm cure |
Why must I report medicines before testing?
Certain acid-suppressing, antibacterial and stomach-lining preparations can temporarily reduce the bacterial load and produce a false-negative breath or stool result. Tell the clinic about recent medicines, the date of any previous course and any medicine you stopped yourself.
Do not stop prescribed treatment solely to prepare for a test. Required intervals differ by test and individual condition. Follow the ordering clinician or laboratory instructions; if a medicine cannot be withheld, say so before testing so the result can be interpreted or another method selected.
Does a positive H. pylori test need treatment?
Treatment commonly combines acid-suppressing and several antibacterial drug classes, sometimes with another stomach-lining related class. The regimen depends on local resistance, previous antibacterial exposure, allergies, liver and kidney function, pregnancy or breastfeeding, and the outcome of prior treatment.
Do not use a relative’s leftovers, shorten the course or substitute medicines yourself. Contact the prescribing clinic if problems occur. If infection remains after a completed course, the clinician reviews previous treatment and any needed investigations before selecting the next approach rather than simply repeating it.
When should eradication be confirmed?
Feeling better does not prove eradication, and having no symptoms does not mean treatment failed. Current guidance emphasises confirming eradication after every completed course. This is generally performed at least four weeks after antibacterial treatment ends using a urea breath test, stool antigen test, or an endoscopic sample in selected situations.
Medicines that could interfere still need to be managed as instructed before the check. A positive result requires review of adherence, previous treatment and possible resistance. Even after eradication, people with gastric atrophy, intestinal metaplasia, prior stomach surgery or other higher-risk findings may need individual endoscopic surveillance.
Can H. pylori spread and should family members test?
H. pylori often spreads within households, probably through oral–oral or faecal–oral routes. Handwashing, safe drinking water, not sharing cups or utensils, using serving utensils and not pre-chewing food for children can reduce cross-exposure.
Household members should not take the same medicines without testing. If a partner or relative is infected, share your age, symptoms, stomach history and family history with a clinician and discuss testing. Treatment is selected only after infection is confirmed.
Which stomach warning signs need prompt care?
Screening can identify infection but cannot rule out every stomach disorder. The following warning signs may require blood tests, endoscopy or other assessment rather than self-treating or waiting for symptoms to settle.
- Vomiting blood, coffee-ground material, black stool or visible blood
- Persistent or recurrent vomiting that prevents eating or drinking
- Difficulty or pain with swallowing, or food repeatedly sticking
- Unexplained weight loss, marked appetite loss or easy fatigue
- Known anaemia, an abdominal mass or worsening upper-abdominal pain
- A first-degree relative with gastric cancer plus new digestive symptoms
If sudden vomiting and diarrhoea affect several household members, also read norovirus symptoms, hydration and cleaning.
Sources for this H. pylori guide
- Taiwan Health Promotion Administration: gastric-cancer prevention and H. pylori screening
- Taiwan Health Promotion Administration: 2026 publicly funded test
- American College of Gastroenterology: treatment and test-of-cure guidance
- NIDDK: dyspepsia and H. pylori testing
Yes. Infection often has no clear symptoms. Testing decisions consider age, ulcer history, gastric-cancer family history, household exposure and current screening eligibility.
No. Infection is an important risk factor but does not mean cancer is present. Symptoms, age, family history and the stomach lining determine whether endoscopy is needed.
Both assess active infection and can confirm eradication. Access, recent medicines, ability to collect a sample and the need for endoscopy guide the choice.
Usually not. Antibodies may remain after the bacterium has cleared, so they cannot reliably distinguish current from past infection.
Yes, follow the advised test of cure. Symptoms do not prove bacterial clearance; testing is generally scheduled at least four weeks after antibacterial treatment ends.
No. Household members can discuss individual testing first. Treatment is prescribed only after infection is confirmed and personal factors are reviewed.
Doctor’s note: a positive result is not the final step
H. pylori may cause no symptoms, and pain relief does not confirm eradication. Return with the result so treatment can reflect previous medicines, allergies and test findings, then complete the advised test of cure. Black stool, vomiting blood, persistent vomiting, swallowing difficulty, unexplained weight loss or anaemia need prompt assessment.
This article provides general health education and cannot replace an in-person diagnosis. Test selection, treatment classes and preparation must be assessed by a clinician for the individual.
Internal medicine and gastroenterology team
