The short answer
Early stomach cancer often causes vague or no symptoms. As it grows, signs can include indigestion, belly pain, a bloated feeling after eating, nausea, and unexplained weight loss. Lasting symptoms should be checked.
Early stomach cancer often causes vague or no symptoms.
Indigestion, belly pain, and a bloated feeling after eating can be signs.
Nausea, unexplained weight loss, and blood in the stool can occur.
These symptoms have many common causes, so lasting ones should be checked.
Choose how you want to read this
The whole article, with every detail and caution.
This page is for anyone with stomach symptoms that worry them, and for the people who care about them. It covers possible signs of stomach cancer, when to see a doctor, and what tests to expect.
The simple version
Stomach cancer often causes vague symptoms early on, or none at all. That is part of why it can be hard to catch early. As it grows, signs like indigestion, belly pain, and weight loss for no known reason can appear.
Possible signs
Symptoms can include:
- Ongoing indigestion or heartburn
- Belly pain or discomfort
- A bloated feeling after eating
- Mild nausea
- Unexplained weight loss
- Blood in the stool or vomit (vomiting blood needs emergency care, see below)
Each of these symptoms can be caused by many conditions other than stomach cancer. Symptoms that last or get worse are worth getting checked.
A fuller list of possible symptoms
Other symptoms that can occur include:
- Poor appetite
- Vomiting, with or without blood
- Swelling or fluid buildup in the belly
- Dark or black stools
- Trouble swallowing
- Jaundice, a yellowing of the skin and eyes
These symptoms may be caused by many conditions other than stomach cancer. But if they last, they are worth a doctor visit.
Usually not cancer, but still worth checking
NCI says these symptoms may be caused by many conditions other than stomach cancer. But they can also be signs of it. So symptoms that last or keep coming back should be checked by a doctor.
Lasting indigestion or belly pain should be checked, even though it is usually not cancer.
Why it is often found late
Stomach cancer often causes no symptoms in its earliest stages. When symptoms do appear, they can be easy to mistake for everyday indigestion. If symptoms do not go away, it is worth seeing a doctor rather than continuing to wait.
H. pylori and other risk factors
Long-term infection with H. pylori, a common stomach bacterium, is a major risk factor for stomach cancer. Smoking and certain diets, especially those high in salted or smoked foods, also raise risk. If you have persistent symptoms and any of these risk factors, mention both to your doctor.
When to see a doctor
See a doctor for:
- Indigestion or belly pain that lasts or keeps coming back
- A bloated feeling after eating
- Trouble swallowing
- Unexplained weight loss
- Any blood in your stool
These symptoms have many possible causes, but they all deserve a proper evaluation rather than guesswork.
Go to an emergency department right away if you vomit blood, or if your stool is black and tarry, especially if you also feel dizzy or lightheaded. These can be signs of bleeding in the stomach or bowel and need to be examined right away. Do not wait for an appointment.
What tests to expect
Your doctor may refer you for an upper endoscopy with biopsy. This test passes a thin, lighted tube through the mouth and down the throat to look at the stomach lining and take tissue samples. NCI also lists barium swallow and CT scans among the tests used.
What to ask your team
- Do my symptoms need an endoscopy?
- Should I be tested for H. pylori?
- What else could explain my symptoms besides cancer?
- What would bring me back sooner than my next scheduled visit?
Sources
Common questions
What are the symptoms?
Signs can include ongoing indigestion or heartburn, belly pain, a bloated feeling after eating, nausea, unexplained weight loss, and sometimes blood in the stool or vomit.
Why is stomach cancer often found late?
Early stomach cancer often causes vague symptoms that are easy to mistake for common problems like indigestion, so it may not be found until it has grown.
Do these symptoms mean cancer?
Usually not. Indigestion and belly pain are far more often caused by common conditions. But because they can signal stomach cancer, lasting symptoms should be checked.
What raises the risk?
Long-term infection with H. pylori bacteria, smoking, and certain diets raise the risk of stomach cancer.
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).
Talk with a trained specialist or navigator
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Fever of 100.4°F (38°C) or higher during chemo, severe pain, or trouble breathing: call your cancer care team right away, day or night. Call 911 for an emergency.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Last updated: 2026-10-16Next planned review: 2027-07-07
Review details and limits
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team 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.
Words to know
Tap any term to see what it means.
Knowledge check
0 of 3 answered
This self-assessment checks understanding of educational content only. It is not medical advice.
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, and this 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 then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. 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.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.