The short answer
Reflux, gastritis and ulcers explain most lasting indigestion. A short list of alarm features changes the plan: swallowing trouble, weight loss, repeated vomiting, anemia, a lump, or black stools.
MedlinePlus notes heart attack pain can feel like bad indigestion and can spread to the arms, neck, jaw or back, so chest tightness with sweating or breathlessness means calling 911.
The NHS advises seeing a doctor for indigestion with severe pain, unintended weight loss, trouble swallowing, repeated vomiting, iron deficiency anemia, a lump in the stomach, or bloody vomit or stool.
NCI lists indigestion and heartburn among early stomach cancer symptoms, and indigestion and painful or difficult swallowing among esophageal cancer symptoms.
NCI links chronic Helicobacter pylori infection to stomach cancer, though it says the evidence does not support testing everyone.
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The full explanation.
When "indigestion" is really the heart
This is the mistake that costs the most. Heart attack pain is often described as bad indigestion.
MedlinePlus says the pain can feel like a tight band around the chest, like bad indigestion, or like something heavy sitting on the chest. It may move from the chest to the arms, shoulder, neck, teeth, jaw, belly or back.
Call 911 if upper belly or chest discomfort comes with:
- tightness, heaviness or pressure in the chest.
- pain spreading to the arm, neck, jaw, back or stomach.
- shortness of breath, a cold sweat, or nausea.
- lightheadedness or a racing heart.
MedlinePlus is direct about this. Do not wait, and do not drive yourself to hospital.
Alarm features that change the plan
Most indigestion is treated first and investigated only if it persists. A short list flips that order.
The NHS advises seeing a doctor if you:
- keep getting indigestion, or are in severe pain.
- have lost a lot of weight without meaning to.
- have difficulty swallowing.
- keep being sick.
- have iron deficiency anemia.
- feel like you have a lump in your stomach.
- have bloody vomit or bloody stool.
Two of those need emergency care rather than an appointment. MedlinePlus lists vomiting blood and dark, tarry stools as signs of gastrointestinal bleeding, which can be dangerous or life threatening. Add dizziness or fainting alongside bleeding and the answer is 911.
Why reflux and ulcers explain most of it
Indigestion is common, and its usual causes are not dangerous.
The NHS describes indigestion as heartburn, feeling full and bloated, feeling sick, burping, and bringing up bitter fluid. It lists the usual drivers: coffee, alcohol, chocolate, fatty or spicy food, carrying extra weight, smoking, pregnancy, stress, a hiatus hernia, and anti-inflammatory painkillers such as ibuprofen.
Stomach ulcers, gastritis and gallbladder problems fill out the rest of the list. All are treatable once identified.
The cancers that can start this way
NCI lists indigestion and stomach discomfort, a bloated feeling after eating, mild nausea, loss of appetite and heartburn as early stomach cancer symptoms. It notes that stomach cancer often has no symptoms early on, which is exactly why lasting indigestion gets taken seriously.
For esophageal cancer, NCI lists painful or difficult swallowing, weight loss, pain behind the breastbone, hoarseness and cough, and indigestion and heartburn.
For pancreatic cancer, NCI names jaundice, pain and weight loss as the main signs, and notes those signs resemble many other illnesses.
None of this makes cancer likely. It explains why "we will treat it and see" has a time limit attached.
H. pylori testing and trial treatment
Helicobacter pylori is a stomach bacterium. NCI says people with chronic H. pylori infection have an increased risk of a stomach cancer called non-cardia gastric adenocarcinoma. It also reports that most experts do not think the current evidence supports testing and treating everyone, partly because of antibiotic resistance. Testing is aimed at people whose symptoms or history call for it.
So a test for H. pylori is often one of the first steps. It can be a breath test, a stool test or a blood test. Treatment is a short course of antibiotics with acid-lowering medicine.
Alongside that, your clinician may review your medicines, stop anything irritating the stomach lining, check a blood count for quiet iron loss, and try a course of acid suppression.
When endoscopy is the right next step
Endoscopy answers what tablets cannot. A thin camera looks at the lining of the gullet, stomach and duodenum, and can take samples.
It is usually offered when an alarm feature is present, when symptoms return after treatment, when the picture is unusual for your age and history, or when anemia has no other explanation.
Ask two questions before you agree. What would this test rule out? And what happens if it is normal?
Tracking symptoms before the visit
Note how long this has lasted and what brings it on. Record whether food sticks, and where.
Weigh yourself and compare with six months ago. Note the color of your stools. List every medicine, including over-the-counter painkillers, and what you have already tried. Stomach Cancer and Esophageal Cancer explain what a fuller assessment involves.
Sources
Words to know
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Common questions
Does persistent indigestion mean I have cancer?
Usually not. Acid reflux, gastritis, ulcers, gallbladder problems, diet, some medicines and stress cause most lasting indigestion. Cancer is one possible cause in certain patterns, but a clinician needs to evaluate the full picture.
How long should I wait?
Chest tightness spreading to the arm, neck, jaw or back, with sweating, nausea or breathlessness, needs an ambulance now. Otherwise the NHS advises seeing a doctor if indigestion keeps coming back or comes with any alarm feature.
What should I bring to the visit?
Bring how long it has lasted, what triggers it, whether food sticks, your weight over the past six months, any vomiting or black stools, every medicine including aspirin and anti-inflammatories, and what you have already tried.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Your next step
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Sources last checked: 2026-08-13 what this meansLast updated: 2026-08-17Next planned review: 2027-07-20
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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