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Cancer Explained
Beginner 4 min read Verified

Stomach Cancer: Signs and Symptoms

A plain-language guide to the signs of stomach cancer, which often appear only as it grows. Based on the National Cancer Institute.

NCI source

Last reviewed: 2026-07-07

The short answer

Early stomach cancer often causes vague or no symptoms. As it grows, signs can include indigestion, belly pain, feeling full quickly, nausea, and unexplained weight loss. Lasting symptoms should be checked.

  • Early stomach cancer often causes vague or no symptoms.

  • Indigestion, belly pain, and feeling full quickly 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.

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The full explanation.

The simple version

Stomach cancer often causes vague symptoms early on — or none at all — which is why it can be hard to catch early. As it grows, signs like indigestion, belly pain, and feeling full quickly become more noticeable.

Possible signs

Symptoms can include:

  • Ongoing indigestion or heartburn
  • Belly pain or discomfort
  • Feeling full quickly when eating
  • Nausea, unexplained weight loss, or blood in the stool or vomit

Usually not cancer

Indigestion and belly pain are far more often caused by common conditions than by cancer. But because they can be signs of stomach cancer, symptoms that last or keep returning should be checked.

Lasting indigestion or belly pain should be checked, even though it is usually not cancer.

When to see a doctor

See a doctor for ongoing indigestion, belly pain, feeling full quickly, or unexplained weight loss. Long-term infection with H. pylori bacteria raises risk, so ask about testing if you have persistent symptoms.

Words to know

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Common questions

What are the symptoms?

Signs can include ongoing indigestion or heartburn, belly pain, feeling full quickly when 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.

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Quick quiz

Test your knowledge

0 of 3 answered

  1. Q1.Why is stomach cancer often found late?
  2. Q2.Which can be a sign?
  3. Q3.Which infection raises stomach cancer risk?

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Related learning map

How this explanation connects to 10 other things you can explore — related topics, terms, questions, practice, and its NCI source.

Stomach Cancer: Signs and Symptoms