Eradicating H. pylori
Also called: Helicobacter pylori eradication, H pylori treatment, stomach bacteria treatment.
Last reviewed 2026-09-16. How this works.
Preventing gastric cancer in infected people Grade A
Randomised human evidence of benefit.
A common stomach germ can cause stomach cancer, and getting rid of it lowers the chance of that happening.
A cheap generic treatment that prevents a cancer, with randomised evidence behind it.
The claim
Helicobacter pylori is a bacterium that lives in the stomach lining of a large share of the world's population. The claim is that finding it and clearing it prevents a cancer that would otherwise develop years later.
What it does
Long-term infection causes chronic inflammation of the stomach lining, and that inflammation is the route to cancer. The International Agency for Research on Cancer classified H. pylori as carcinogenic to humans in 1994, and its working group now describes gastric cancer as largely an infection-caused disease.1
The evidence
A systematic review searching four databases to December 2024, including only randomised controlled trials, found that eradication reduced the risk of gastric cancer. The reduction was still present when the analysis was restricted to healthy adults rather than people already under investigation.2
An International Agency for Research on Cancer working group reported gastric cancer incidence down 36 percent and mortality down 22 percent in otherwise healthy people.1
In people who had already had an early gastric cancer removed at endoscopy, an open-label randomised trial measured whether a second, separate cancer appeared elsewhere in the stomach.3
The number needed to treat in the pooled randomised analysis was 332, and 476 among healthy adults. Most people who are treated would never have developed the cancer. That is what prevention looks like when it is measured across a population, and it is not a statement about any one person.2
This entry also corrected the book's own closing argument. The Grade Table used to say that every A is something that cannot be bought. This one is a course of cheap generic antibiotics that prevents a cancer, and the generalisation was too neat.2
The studies this rests on
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Pooled randomised trials of H. pylori eradication and gastric cancer2
A meta-analysis, summarising randomised trials, measured a clinical outcome.
eradication reduced gastric cancer risk, with the reduction still present among healthy adults.
relative risk 0.61, interval 0.47 to 0.79. number needed to treat 332; healthy adults 0.67, interval 0.48 to 0.93, number needed to treat 476
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Eradication after endoscopic resection of early gastric cancer3
A randomised trial, open label, measured a clinical outcome.
reported on the incidence of metachronous gastric carcinoma after endoscopic resection.
What is absent
No trial has reported a cancer benefit from eradication treatment in people who do not carry the infection. Every randomised trial behind this grade enrolled people with a confirmed infection.
Scope: people without a confirmed H. pylori infection.
Established by trial scope, checked 2026-09-16. Result: every trial pooled in this record tested eradication in people who carried the organism.23
No trial behind this grade tested eradication as a treatment for a cancer that has already developed. The endoscopy trial measured whether a new cancer appeared after an early one was removed, which is prevention rather than treatment.
Scope: treating an existing cancer, any site.
Established by trial scope, checked 2026-09-16. Result: every endpoint pooled here is the appearance or the mortality of a cancer, not the response of one already present.23
What to ask
Would testing me for H. pylori change anything about my care, and is that test something you would consider?
The dish-to-person gap
Eradication is a treatment a clinician prescribes and confirms by testing, not a compound a reader obtains and takes alone, so the dish-to-person comparison does not apply to it.
When to call your team — no warning signs are recorded
If this is something you are considering or have already had done, the people treating you can only weigh it if they know about it. That is true when nothing has been written down here, and it is most true then.
This treatment is prescribed and followed up by a clinician, so the register records no signs of its own here. That is not a statement that nothing can go wrong; it is a statement that the person who prescribed it is the person watching for it.
Interactions
This treatment is prescribed and followed up by a clinician who holds the reader's full medication list. The register does not check one prescribed treatment against another.
The whole interaction list, and how to turn it into a pharmacy review request.
Find a trial instead
Eradication is given in routine care rather than studied in recruiting trials, so the register does not build a trial link for it.
References
Helicobacter pylori screen-and-treat programs for gastric cancer prevention. IARC Working Group report, New England Journal of Medicine 2026.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 23 note 16.
The relationship between the eradication of Helicobacter pylori and the occurrence of stomach cancer: an updated meta-analysis and systematic review. BMC Gastroenterology 2025.
doi:10.1186/s12876-025-03886-z
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 23 note 17.
Fukase K, Kato M, Kikuchi S, Inoue K, Uemura N, Okamoto S, et al, Japan Gast Study Group. Effect of eradication of Helicobacter pylori on incidence of metachronous gastric carcinoma after endoscopic resection of early gastric cancer: an open-label, randomised controlled trial. Lancet 2008;372:392-397.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 23 note 18. The author string is abbreviated in the source that was read and has not been expanded.