Colonoscopy Guide
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When to call a doctor

Warning signs after a colonoscopy

Call 911 or go to the emergency room

if you faint, have trouble breathing, have chest pain, or are passing a lot of blood.

Call the center that did your colonoscopy

If you can't reach them, go to urgent care or the emergency room. Call if you have:

  • Belly pain that is severe or getting worse
  • A belly that is hard or swollen
  • Fever or chills
  • Vomiting, or you can't keep liquids down
  • More than a small amount of blood from your bottom, or bleeding that doesn't stop
  • Feeling dizzy or weak

Good to know: a little blood is common if polyps were removed. Bleeding can sometimes start up to two weeks later, so keep these signs in mind for that time.

During your prep

Call the practice if you keep vomiting, feel very dizzy, or can't finish the prep.

Sources: American Cancer Society; US Multi-Society Task Force on Colorectal Cancer.Clinical review: Dr Aasma Shaukat · 29 Oct 2026

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