You have had trouble with your stomach for months. A burning feeling, a full belly after a few bites, and sometimes you feel sick for no clear reason. Your GP may have prescribed omeprazole, and for the first few weeks it helped. You still take it, but the moment you skip a couple of days the symptoms come back. So why is that?
The stomach bacterium Helicobacter pylori is more common than people think. About one in five of the Dutch population carries it, and among the people who go to their GP with stomach problems it is one in three.
If your roots lie around the Mediterranean, in Eastern Europe, the Middle East, Asia, Africa or Latin America, that chance is higher still. Most people never notice a thing. But in some carriers this bacterium slowly changes the whole climate in the stomach, and that is exactly what you feel.
The GP guideline is clear that anyone with persistent or recurring stomach problems should be tested for this bacterium, and since 2025 even before you start on an acid blocker. Even so, we still speak to people who took such a tablet for years and were never tested.
What Helicobacter pylori does in your stomach
Your stomach wall has a protective layer of mucus. That mucus lies over the wall like a blanket and keeps the acid at a distance, so your stomach does not digest itself. Helicobacter pylori settles under that blanket, between the mucus and the stomach wall.
To survive there, the bacterium produces an enzyme called urease. That enzyme turns urea into ammonia, and ammonia neutralises acid. So the bacterium creates a less acidic environment around itself. Handy for its survival, but your immune system reacts to it. Inflammation of the stomach lining can develop in the spot where it sits, and that inflammation can be there a long time before you notice anything.
How do you catch it, and is it contagious?
The bacterium passes from person to person, and infection almost always happens in early childhood, usually within your own family. A long-running study that followed children from birth into adulthood shows this well: around the fifth year of life just over two percent of children became infected each year, and by the age of twenty that was down to three in a thousand per year. Picking it up as an adult is possible, but it is rare.
So the inflammation starts early. The consequences you notice, such as a stomach ulcer or a stomach that starts making less acid, usually take decades to show up. That is one of the reasons why almost nobody makes the link between a bacterium from their childhood and the stomach problems they have now.
The question that always follows: should my partner get tested as well? Partners of carriers are indeed more often carriers themselves, but whether one reinfects the other after a successful course is a good deal less clear. Research that put the bacterial strains side by side often did not find the same strain. Testing your whole household as a matter of course is not usual practice in the Netherlands. If your partner or one of your children has stomach problems of their own, testing is worth raising with the GP.
And no, the bacterium does not clear up by itself. Without treatment it usually stays for life, including the years when you notice nothing.
Why your acid symptoms are not always caused by too much acid
This is the part that often gets skipped. Most people, and honestly plenty of practitioners too, think of too much acid the moment they hear stomach problems. That is not always the case. It depends on where in the stomach Helicobacter pylori has settled.
If the inflammation sits mainly in the lower part of the stomach, acid production can go up. That gives the classic picture: a burning feeling, sometimes with an ulcer in the duodenum. If the inflammation sits more in the middle section of the stomach, where the acid-producing cells are, the opposite happens. Once those cells are damaged, less acid comes out over time, not more.
And that second picture is not the exception. Of the people who carry this bacterium for years, roughly one in ten gets the picture with more acid. In most of them the inflammation is spread more widely across the stomach and acid production goes down instead.
That feels confusing, because too little stomach acid causes symptoms that many people recognise as too much acid. Food that sits in your stomach like a brick for hours, burping, a bloated feeling, a burning oesophagus. You can read more about why that happens, and which factors play a part when there is too little acid, in the article on the causes of acid symptoms.
The result is that someone with too little stomach acid gets a medicine that suppresses acid production even further. The symptom softens, but the underlying problem carries on.
The symptoms that come with it
Not every carrier gets ill, and far from every stomach complaint comes from this bacterium. But there is a pattern that keeps coming back in people who do have it:
Is there a nagging or burning feeling high in your belly, particularly on an empty stomach? Are you full after a small portion? Do you often have nausea, burping or bad breath that brushing does not shift? Has your appetite dropped without a reason you can name? Are you tired in a way that sleep does not fix? And do those symptoms come back the moment you stop the acid blocker?
Answering yes to several of these proves nothing on its own. It is reason enough to have yourself tested, and to know what that test can and cannot tell you.
There are also symptoms that cannot wait. Go to your GP if you notice that you are losing weight without setting out to, if you vomit blood or something that looks like coffee grounds, if your stools are black or tarry, if swallowing is difficult, or if you have anaemia that nothing explains. Those are signals that need investigating first. Helicobacter pylori can play a part in them: around eight in ten ulcers in the duodenum and half of all stomach ulcers are linked to this bacterium, and in the large majority of stomach cancers it plays a role. That last point sounds heavier than it is, because the other way round, of all the people who carry the bacterium, only a very small number ever get stomach cancer.
Why your test can come back false negative because of your acid blocker
Here is a practical problem that costs many people unnecessary time in working out what is wrong. The two common tests for Helicobacter pylori, the breath test and the stool test, look for an active bacterium.
If you take an acid blocker such as omeprazole or pantoprazole, the bacterium does not disappear. Something else happens. Your stomach becomes less acidic, and the bacterium responds to that in two ways. There are fewer of them, because a tablet like that also inhibits the bacterium directly. And the little channel through which urea reaches its urease closes in a less acidic stomach. That conversion of urea happens to be exactly what the breath test measures. Research shows that the breath test therefore comes back as a false negative in up to four out of ten users. Stop the tablets for a week and almost everyone tests positive again, and after two weeks that picture has recovered.
That is why it matters to stop the acid blocker at least two weeks before the test, and to wait at least four weeks after a course of antibiotics. Only do this after talking it through with your GP, because stopping is not something to arrange on your own.
What often happens is that someone who took an acid blocker for years was tested at some point while still swallowing that tablet, and on the strength of that one negative result was told the bacterium is not the problem. Or to put it another way, that it was never established. What else an acid blocker does in your gut and your digestion is covered in the article on acid blockers and gut problems.
How to find out whether you have it
There are four ways, and they do not tell you the same thing.
The breath test and the test on your stools show whether the bacterium is there now. Those are the tests you want when the question is: do I have it, yes or no. A gastroscopy adds a view of the stomach wall itself, and is done when there are warning signs or when the symptoms persist. A blood test for antibodies only says that you had it at some point; it can still be positive years after a successful course and is therefore unsuitable for checking whether you are rid of it. That last point is also the answer to the question of whether a self-test from the chemist is worth anything: many of those tests measure antibodies in blood, so they do not tell you whether the bacterium is still there now.
In our practice the bacterium usually comes to light through the stool test, which looks not only for Helicobacter pylori but at the whole picture: the make-up of your gut bacteria, overgrowth of bacteria, yeasts and parasites, and how well you digest your food. That is useful, because the bacterium is almost never the only thing going on.
The course often works, and symptoms still linger for some
Once the bacterium is found, the treatment is an eradication course: two antibiotics at the same time plus an acid blocker, for ten days. Those ten days are no accident; the course was extended because the bacterium is becoming less sensitive to the usual antibiotics. It is a tough course, and it works in most cases. Always check whether it succeeded, with a breath test or a stool test, at least four weeks after the last tablet. That too is now the advice to GPs.
Even so, some people keep their symptoms. There are two explanations for that which do not rule each other out. The first is that years of inflammation changed the stomach lining, and recovery takes time. The second is the course itself: two antibiotics at once are also a major disruption for your gut bacteria, and that disruption causes symptoms which many people do not connect to the course. You can read what happens in that case, and how long it can last, in the article on gut problems after antibiotics.
If the symptoms continue after the course, there are three possibilities side by side. The bacterium is not gone, and the follow-up test shows that. The bacterium is gone but your stomach has not recovered yet. Or the bacterium is gone and your gut has taken the hit from the antibiotics. Those three call for completely different things, so the order is: the follow-up test first, conclusions after that.
Has anyone tried to treat the Helicobacter in your case? The first question is whether anyone checked that the treatment was successful. The second is whether anyone looked afterwards at what was left behind in the gut.
What you can check for yourself
Run through these four questions. Have you ever been tested for Helicobacter pylori, and if so: were you taking an acid blocker at the time? After an eradication course, did anyone check that the bacterium really was gone? Have your vitamin B12, iron and vitamin D been measured at some point? The bacterium can also affect how you digest and absorb your food, and with unexplained iron deficiency anaemia or a B12 deficiency, treating the bacterium is even an international recommendation. Those deficiencies are exactly why tiredness turns up in this list so often. And after the bacterium was treated, did anyone also look at your gut and your gut bacteria?
Four times no is more common than you would think. These are not complicated questions, but they do change the direction of the conversation.
Frequently asked questions about Helicobacter pylori
Is Helicobacter pylori contagious?
Yes, it passes from person to person. Almost always that happens within the family, and usually in childhood. Later in life you rarely pick it up. Testing your partner is not standard, but it is an option if they have stomach problems too.
Does the stomach bacterium go away by itself?
No. If nothing is done about it, it stays. That does not mean everyone needs treating, plenty of people never have any trouble from it.
How do I know whether I have it?
You can look into that with a breath test or a stool test. One thing matters there: you must not have taken an acid blocker for at least two weeks, otherwise the result is wrong. A blood test only tells you whether you ever had it.
Why do I keep symptoms after the course?
That can mean three things. Perhaps the bacterium was not treated properly. Perhaps it is gone but your stomach lining simply needs time to recover. And the treatment may have disrupted your gut bacteria, which brought on other symptoms. You can look into that with a stool test.
Can Helicobacter pylori come back?
If the course worked, you rarely get infected again. If your symptoms come back and the test is positive again, the treatment may not have been successful.
To close
Your stomach does not speak in words. It gives a burning feeling, a full belly, nausea for no reason, and those signals are so general that they nearly always get the same answer: suppress what you feel.
The question underneath is a different one. Why does your stomach react the way it does, and where does that come from? And Helicobacter is one possible cause.
If you want to know what is going on in your situation, a therapist at First Aid for Your Gut will look at it with you. Read more about our personal guidance and book a free thirty-minute introductory conversation. No obligations, just an honest conversation about what is going on with you and what we can do for you.