Can I Drink Coffee Before a Colonoscopy?

Under certain circumstances, a cup of black coffee may be allowed before a scope

Can you have a cup of coffee the morning of your colonoscopy? Maybe. But it certainly won't look like this one. Image © All Rights Reserved by Leonard Kong Photography / Moment / Getty Images

Preparing for a colonoscopy usually requires a certain amount of fasting time, where no food or only certain food is allowed. Even liquids may be off the menu after a certain point, especially the morning of the test. This leaves people wondering if they can still have their morning cup of coffee before a colonoscopy.

A colonoscopy is a test that is used to see inside the colon (the large intestine).

A colonoscopy is a test that's commonly done in people over the age of 50 in order to screen for colon and rectal cancer. People over the age of 50 are at increased risk for developing colon cancer. Colonoscopy is  also used to diagnose many other digestive diseases and conditions, such as inflammatory bowel disease (Crohn's disease and ulcerative colitis). 

What Happens During A Colonoscopy

During a colonoscopy, a tube with a light on the end is inserted through the anus and rectum and into the colon. In order to see the colon walls and so the doctor can check for any signs of disease during this test, the large intestine must be free of fecal matter (stool). Clearing the stool from the colon is commonly done the day before a colonoscopy with a combination of laxatives and enemas.

Coffee (without any milk products) may be permitted only several hours before the colonoscopy. This means that in order to drink a cup of coffee in the morning, the test would need to be scheduled in the late morning or the early afternoon.

For a colonoscopy that is scheduled in the morning, there may not be enough time between that morning cup of coffee and the test, so skipping it altogether would be recommended. Check with your doctor if you have any questions about your prep.

Check the Prep Instructions

Fasting (not eating for several hours) is also a component of the preparation for a colonoscopy.

The duration of the fast will depend on several factors, such as the time of the actual test. In many cases, colonoscopies are done in the morning in order to avoid having patients fasting all day long before their test.

Every physician will have their own colonoscopy prep instructions, and those directions should be followed closely. The day before the test is generally devoted to prepping, and in most cases, patients are advised to follow a clear liquid diet starting in the late afternoon. Clear liquids include water, tea, coffee, ginger ale, 7-Up or Sprite, apple juice, and white grape juice. Sugar, honey, or artificial sweeteners are generally allowed in tea or coffee, but check with your doctor to be sure.

Food And Drink Not Allowed

What is not allowed prior to a colonoscopy is milk, soy milk, creamer, or any other dairy product. These should not be taken in coffee or tea before a colonoscopy. Depending on the time of the test, even clear liquids must be discontinued a few hours prior to the colonoscopy. For a morning test, a morning cup of coffee may not be allowed (check the prep instructions or call the doctor's office if the instructions are unclear). For an afternoon test, a morning cup of coffee might be permitted (again, without any dairy products), but could be limited to just one cup, and only several hours before the test.

If there is any doubt about the prep instructions, check with the physician's office. Accidentally eating or drinking something too close to test time could affect the results, and possibly require a second test to be done (and therefore, a second prep). If there's any doubt, skip the morning cup of coffee and wait until after the test.

A Word From Verywell

Here are the rules of thumb when it comes to drinking coffee prior to a colonoscopy, but always check with the gastroenterologist if there's any questions:

  • If a colonoscopy is scheduled for the early morning, a morning cup of coffee is not recommended
  • For a colonoscopy later in the day, coffee or other liquids may be allowed several hours before the test (check with your doctor or nurse about exact timing)
  • Coffee is a clear liquid, and can be had during the period of the colonoscopy prep when clear liquids are allowed
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