Gastroparesis: when the stomach empties too slowly

You are sitting in front of half a plate. After four or five bites it is over, as if someone had pulled a door shut from the inside.

In the evening nausea joins in. Sometimes you bring up something you ate in the afternoon, barely changed, still recognisable. The scales show less than three months ago, and you did nothing to make that happen.

At the doctor there was a gastroscopy. The stomach looked fine. No ulcer, no tumour, no narrowing. You were handed a note with something about an irritable stomach on it, and the feeling that this was meant to settle the matter.

Many people know exactly this pattern. And for some of them there is a word that was not on any note: gastroparesis.

I am not writing this text so that you can hand yourself a diagnosis. I am writing it so that you can ask the right questions, and so that you can recognise when it is no longer about questions but about speed.

What gastroparesis is, and what it is not

Start with the word. Gastro means stomach, paresis means paralysis. And that is exactly where the misunderstanding begins.

The stomach is not paralysed. It keeps working. It only works too slowly and too poorly coordinated to pass a meal on within the usual time. That sounds like quibbling over words, but it matters. A paralysis sounds final. The course is not.

The actual definition consists of three parts, and all three have to come together.

The third point is the one that most often gets lost. It is at the same time the most important, because a narrowing at the stomach outlet causes exactly the same symptoms as a sluggish stomach. Anyone who reverses the order can miss an obstruction and call it gastroparesis.

The symptom picture, spelled out

Nausea and vomiting count as the cardinal symptoms in the European consensus. Added to them are the complaints that typically show up with the meal: you are full after a few bites, a pressure stays in the upper abdomen, and for a long time nothing moves.

The vomiting has one peculiarity in this picture. It often comes without the usual run up, and what comes up is sometimes hours old and still recognisable as a meal. People describe this as shaming and frightening at the same time, because it does not feel like an ordinary upset stomach.

Unintentional weight loss belongs to the picture as well. It is not a side effect to wait out, it is one of the reasons why this picture belongs in medical care.

How common this really is

Precision pays off here, because very different numbers circulate online.

A review by Adil Bharucha puts these numbers in context and points out explicitly that most frequency studies were carried out in selected case series and not in the general population [Mechanism Review]. Anyone who applies numbers from specialist clinics to themselves is calculating with the wrong denominator.

And now you know why a doctor who wants a gastroscopy first with this picture is not brushing you off. They are following the definition.

Where it comes from: eight roads to a slow stomach

The most common question after the diagnosis is: why me?

There are several answers to that, and none of them fits everyone. Some roads are well studied, others are barely more than a plausible story. I go through them one by one and say each time how solid the number is.

1. Diabetes, the best known road

Diabetes is the best documented cause. Over years, a high blood sugar can damage the fine nerves that steer the movement of the stomach. That is the same nerve damage that makes feet go numb, only in the autonomic nervous system.

The finding on heartburn is interesting because it is rarely mentioned. Early heartburn in type 1 diabetes could be a hint at a beginning involvement of the autonomic nervous system. A prescribed acid blocker is neither stopped nor changed in dose on your own, that belongs in medical care. What acid blockers can do and where their limits are is set out in detail in the article on heartburn and acid blockers.

2. Idiopathic, the largest group

Idiopathic means: no cause can be found. In specialist centres this is the largest group, and it has a striking profile.

3. After an infection

In one in five idiopathic cases the whole thing began after a gastrointestinal infection. You may know the same pattern from irritable bowel syndrome, where the post infectious road is particularly well described. How that runs is in the article on irritable bowel and the search for causes.

4. After operations

Precision is needed here, because a lot of half knowledge circulates. This is not about every anaesthetic and not about every abdominal operation. It is about major procedures in which the vagus nerve or the anatomy at the stomach outlet is touched.

5. Connective tissue diseases

In systemic sclerosis the connective tissue changes throughout the body, and the muscle layer of the digestive tract is not spared. A review states that the oesophagus may be involved in around 90 percent and the intestine in 40 to 70 percent of those affected [Mechanism Review].

The evidence on this is thin, though. What is available are case reports, that is the lowest level of evidence there is [Case Series, n=2]. A French paper describes two women with long standing systemic sclerosis whose symptoms improved after an endoscopic procedure at the stomach outlet. Two people do not allow a recommendation. They allow a question.

6. Parkinson

In Parkinson disease, digestion is often affected earlier than movement. That fits what is being discussed about the spread of the disease along the autonomic nervous system.

Bacterial overgrowth of the small intestine turns up here as an accompanying finding. What it is and how it is established is in the article on SIBO in the small intestine.

7. Medicines

The medication list is the part that can most readily be moved, and therefore the most interesting one. Opioids, anticholinergics and some psychiatric medicines can slow the stomach. For the opioids the evidence is densest.

Important with that: a painkiller that was prescribed to you is not stopped because of a blog article. What you can do is bring the list along and ask about it. Every change to painkillers, antidepressants or other long term medicines belongs in medical care.

8. What happens in the tissue

That leaves the question of what is actually different at the cell level. For that there is one of the few studies in which tissue from the full thickness of the stomach wall was taken and looked at.

The same Cajal cells turn up again in the small intestine when the question is why a bacterial overgrowth so often comes back. I do not explain it twice here, it is set out in detail in the article on motility and relapses in SIBO.

And now you know why the first question after the diagnosis should be: which road is it in my case?

The weight loss injections: a new and frequent topic

This question has come up almost daily for two years. It often comes with fear in the tone, because in the media the word stomach paralysis stands next to the word weight loss injection.

I start with the part that is least understood: the slowing is not a fault of the medicine. It is part of how it works. GLP-1 receptor agonists slow gastric emptying among other things, and part of the feeling of fullness comes from exactly that. How these medicines work overall is in the article on how the weight loss injections work.

So the question is not whether they slow the stomach. They do, and that belongs to the documented mode of action. The question is how often this turns into a condition.

A second, independent survey from the American All of Us cohort found a gastroparesis diagnosis in 5.1 percent of new users of a GLP-1 agonist. That sounds like a lot, but it is a cross section without a control group, and abdominal pain appeared there in 57.6 percent. Numbers like these describe who carries which code in a database, not how often something arises causally.

Gastroscopy and anaesthesia: the practical question

This is the question I am asked most often. Do I have to stop the injection before an examination?

The answer consists of two numbers that point in different directions.

Everything else about the side effects of these medicines I do not unfold here. It is in the article on the side effects of the weight loss injections.

And now you know why the answer to the weight loss injection question is neither an all clear nor an alarm, but a number with a wide confidence interval.

How it is measured, and why the scope comes first

If you are wondering why nobody simply looks into the stomach and says how fast it is: that is exactly what cannot be done. The movement cannot be seen directly. All that can be followed is how much of a meal is still inside after a set time.

That is why the road to the diagnosis looks the way it does.

The scintigraphy, step by step

It counts as the reference method. The principle is simpler than the name suggests.

You are given a standardised test meal. Standardised means: not just any breakfast, but a set, low fat meal based on egg white, mixed with a very small amount of a radioactive marker. A camera is then held over your abdomen, at four fixed time points: right afterwards, after one hour, after two hours and after four hours.

From German practice information, so not from studies, come the organisational details: plan for about five hours, arrive fasting for at least six hours, and expect a radiation dose in the order of around 1.3 millisievert. That is roughly what you take in from natural radiation in Germany over half a year anyway. I mark these figures explicitly as practice information, not as study numbers.

What I deliberately do not write here are threshold values in percent. Those belong in the conversation about your report, where someone brings them together with your situation, and not in a guide article, where they invite self interpretation.

Without radiation: the breath test

The capsule

There is also a swallowable motility capsule that measures pressure, acidity and temperature along its way. Its advantage: it also records how long the small intestine takes. In the Parkinson study further up, exactly this method was used. In Germany availability is limited.

And now you know why a second value may look different without anything new having happened.

Gastroparesis or irritable stomach: the distinction almost nobody makes

Now comes the part I consider the most important in this article, because clinically it concerns the most frequent mix up.

Next to gastroparesis stands a second picture: functional dyspepsia, colloquially the irritable stomach. According to the Rome IV criteria it is about fullness after eating, early satiety, upper abdominal pain and upper abdominal burning that remain unexplained after a routine work up [Guideline]. What the irritable stomach is exactly I do not explain again here. That is set out in detail in the article on functional dyspepsia.

Here it is only about one question: how do you tell the two apart?

The honest answer: from the symptoms, practically not at all.

One limitation absolutely belongs with it: these were tertiary care centres. People end up there when a lot has already remained unclear. In a family practice the distribution looks different. Even so the finding stays remarkable, because the same people were measured twice.

Why the guidelines separate them anyway

At this point it would be easy to place yourself above the specialist field. I consider that wrong, for two reasons.

First: without an objective criterion the diagnosis would be arbitrary. Everyone with nausea and fullness would get the label, and then it would no longer mean anything. The measurement can protect against overdiagnosis.

Second: the categories have different consequences. With a confirmed, marked emptying disorder the nutritional state belongs under closer watch, and some procedures only come into consideration then at all.

Since 2025 Germany has had its own S1 guideline on functional dyspepsia, issued by the German Society for Neurogastroenterology and Motility [Guideline]. On gastroparesis there is nothing of its own here. That gap is itself a finding. It explains why the information people receive turns out so differently.

And now you know why the question gastroparesis or irritable stomach is less of an either or question than the two words suggest.

What is actually studied when it comes to eating

On this topic the same order meets you almost everywhere: low fat, low fibre, small portions, liquid components.

These recommendations are not wrong. They are only justified differently in one place than almost everywhere it is written. And for this whole field there is exactly one randomised trial.

And now the secondary finding the authors noted themselves and which is rarely mentioned alongside: the intervention group took in more fat than the comparison group.

That changes the order. In this trial the effect did not come through less fat. It may have come through the texture of the meal. It remains a secondary finding of a single study, and that is exactly how it should be read.

The European consensus confirmed nutritional therapy as one of only three accepted treatment options [Guideline]. The detailed rules behind it, meaning smaller portions, less insoluble fibre, softer texture, come mostly from clinical tradition and not from studies. That is no reason to discard them. It is a reason to name them for what they are.

What I deliberately do not write here: no meal plan, no portion sizes, no number of meals per day. What fits you depends on your weight, your blood sugar, your symptoms and your daily life. That belongs in a dietary consultation, not in an article.

Fibre: a different rule applies here

In the rest of the gut cluster I keep encouraging you to eat more plant variety. With a very slow stomach the opposite applies temporarily, at least for the coarse, insoluble fibres. They need more breaking down work and can in extreme cases clump together into a solid mass.

That this exception exists does not devalue the general rule. Why the famous number 30 is more nuanced than it sounds is in the article on the fibre myths.

The bigger risk is called undersupply

Now comes the section I consider the most important one in practice and the one that often gets too little space in guide texts.

Iron and zinc are the two I meet most often, because both depend on a working uptake in the upper digestive tract. What iron deficiency has to do with the gut is in the article on iron deficiency and absorption problems. Why the other micronutrients hang together as cofactors in energy metabolism is in the article on micronutrients and energy.

Two notes belong right beside this, because both substances are named above. Vitamin K can affect how coumarin anticoagulants work. And potassium is not something to supplement on your own with impaired kidney function. What is actually missing in you is shown by a measurement, and what follows from it belongs discussed.

And now you know why dietary counselling with this picture is not a nicety but the part with the best evidence.

Medicines and procedures: what they can do and where they end

Before I discuss anything individually here, the frame belongs in front of it. It comes from the European consensus process, and it is unusually open.

I do not read that as weakness. I read it as honesty. Anyone who says of two thirds of their own questions that there is no agreement makes the field more honest, not worse. And it explains why the information people receive varies so much.

All the agents named in this section are prescription only. They belong in medical hands, and existing medication is never changed or stopped on your own. I give no regimens here. Where an amount appears, it is the dose from the study in question and not a recommendation to you.

Prokinetics

Metoclopramide is the best known representative. It is prescription only. What matters is the limit the European Medicines Agency drew after its 2013 review, in force since 2014 [Regulatory decision]: use is restricted to short periods of at most five days, and the long term treatment of chronic pictures such as gastroparesis is no longer among the approved indications. Anything beyond that would be use outside the marketing authorisation, that is off label, with an extended duty of explanation and justification on the prescribing practice.

The reason for that limit is a movement disorder, tardive dyskinesia. It is rare, but it can persist after the medicine is stopped. Other possible unwanted effects come on top, among them tiredness, diarrhoea, inner restlessness and motor restlessness. With bleeding, an obstruction or a perforation in the digestive tract, with epilepsy, with Parkinson's disease and after a previous tardive dyskinesia, the substance must not be given [Product information].

How high the tardive dyskinesia risk is has been reassessed twice. A review from 2010 arrived at clearly below 1 percent instead of the 1 to 10 percent previously assumed [Mechanism Review]. A reassessment from 2019 arrived at an order of magnitude of about 0.1 percent per 1,000 patient years and named the risk groups: older women, people with diabetes, people with liver or kidney failure and people on concurrent antipsychotic medication [Mechanism Review]. The same paper names the regulatory restriction on long term use in the same breath.

Both papers estimate the risk lower than was previously assumed. They do not lift the restriction. What follows from that in the individual case is weighed up by the prescribing practice, not by a blog article.

The 5-HT4 agonist

What did not respond

The gastric pacemaker

The endoscopic pyloric division

Herbal options, honestly placed

Ginger is the remedy people ask about most often. There is a decent small study on it, and its result cuts both ways.

A second small randomised study in 32 ventilated people in an intensive care unit found better tolerance of tube feeding and more ventilator free days on ginger extract [RCT, n=32]. That is a completely different situation from yours, and I mention it only so that you know what statements about ginger rest on.

On acupuncture it is widely said to be the complementary measure with the best results. I did not find a solid primary source for that in preparing this article, and in the European consensus process no agreement was reached on complementary procedures. That does not mean there is nothing to it. It means the evidence does not carry such a sentence.

Bezoars, briefly and without home remedies

When food residues stay in the stomach for a very long time, they can clump together into a solid mass, a bezoar. That is rare and it is one of the reasons why gastroparesis belongs in medical care. Home remedy ideas circulate for bezoars. I write none here. A bezoar belongs assessed endoscopically and treated medically.

And now you know why I always ask about the comparison group with this topic.

Blood sugar, vagus and stress: the three adjusting screws alongside

There are three things that can slow the stomach without showing up in the diagnosis. They are the reason why the same person can eat normally on some days and gives up after three bites on others.

The blood sugar

Now comes the counter evidence, and it belongs directly alongside. An Austrian working group changed the therapy in ten people with type 2 diabetes. The fasting value fell from 11.7 to 7.9 mmol/l. Gastric emptying stayed unchanged. So short term peaks can slow things down, but the brake does not release again straight away when the values get better over a week. Ten people are few, and that belongs said alongside.

In diabetes this turns into a loop that I often explain: a slow stomach can make it unpredictable when the sugar from a meal arrives. Unpredictable curves make control harder. High values can slow the stomach further. Where this loop can best be broken depends on the individual case. What blood sugar spikes are at all and what influences them is in the article on blood sugar spikes and nutrition.

Stress

What matters to me here is the attitude. Stress is an amplifier here, not a diagnosis and certainly not an accusation. In the American registry, 36 percent had severe anxiety and 18 percent severe depression. That is an accompanying finding. Anyone who does not know for months whether a meal will stay down becomes tense from that, and not the other way round.

The vagus

The vagus nerve steers a large part of stomach movement. So the obvious idea would be to stimulate it. There is a controlled study on this, and it has one important catch.

Yi Zhu and a Chinese team stimulated the vagus branch at the ear and compared that with a sham stimulation. The adjustment of the stomach to the meal improved (P = 0.008), as did the share of regular gastric waves and, after two weeks, the symptoms and the anxiety and depression scores. The catch: the people studied had functional dyspepsia, not gastroparesis. That limitation is not a formality, it decides how far the result carries.

How the gut brain axis hangs together overall and what can actually be influenced at the vagus is in the article on the gut brain axis and vagus stimulation. Here it stays with these two sentences.

And now you know why the question about good and bad days in the consultation is not politeness but diagnostics.

When it becomes urgent, and what a sensible next step looks like

Up to here it was about sorting things out. Now it is about speed.

There are situations in which no guide article and no search for causes is called for any more, but a medical assessment, and promptly.

And for the acute case: with persistent vomiting and circulatory weakness, with severe abdominal pain, with vomiting blood or with impaired consciousness, the emergency department or the emergency number is the right route. In Germany that is 112. Not an appointment next week.

One more word about a differential diagnosis that belongs with recurrent vomiting and belongs named factually: cannabinoid hyperemesis syndrome. In the Rome IV criteria it is a category of its own and it concerns people who use cannabis regularly. Said without moralising: if that applies to you, it belongs on the table at the medical appointment, because it changes how things are read.

The sequence I consider sensible

What can be said about the course

The word everyone is looking for here I deliberately avoid, because the data do not carry it. What can be said is the following.

When the symptoms began after an infection, the follow up looked good: all eleven people followed reported a gradual improvement, stayed weight stable and able to work. Eleven people are a small number, and the study looked backwards. With other causes the course depends on the cause according to the European consensus, and that is exactly how cautiously the consensus is worded there.

And now you know why I started this text with the order and not with the treatment.

Frequently asked questions about gastroparesis

Where the stomach docks onto the rest of the body

A slow stomach does not stand on its own. It hangs on the nutrient supply, on the nervous system, on the blood sugar and on what happens further down the digestive tract.