What is Helicobacter pylori?

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Helicobacter pylori is a bacterium that can infect the lining of the stomach. Despite the highly acidic environment of the stomach, this bacterium is able to survive thanks to adaptive mechanisms that allow it to colonise the gastric wall and, in some cases over time, cause chronic inflammation of the stomach.

It is a very common infection worldwide and, in most cases, it can persist for years without causing any symptoms. However, in some people it may lead to digestive disorders such as chronic gastritis, gastric or duodenal ulcers and, less commonly, it may contribute to the development of stomach cancer or a type of gastric lymphoma.

For this reason, detecting and treating the infection can be of significant clinical importance.

How many people are affected?

It is estimated that approximately 40–50% of the world’s population is infected with Helicobacter pylori, although prevalence varies according to region and socioeconomic conditions.

Although prevalence is lower in developed countries than in developing countries, it remains a frequent infection.

The infection is usually contracted during childhood and can persist for life if left untreated.

Substantiated information by:

Joan Llach Roca

Published: 31 March 2026
Updated: 31 March 2026

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What is Helicobacter pylori?

How many people are affected?

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