Signs That You May Need a Colonoscopy

Table of Contents
View All
Table of Contents

A colonoscopy is a procedure in which a long, flexible instrument with a tiny video camera is inserted into the rectum to view inside the colon (large intestine). The test helps determine the causes of various gastrointestinal problems. A colonoscopy is also performed to screen for colon cancer and precancerous lesions.

Spotting colon cancer early with a colonoscopy can improve your outlook and, in some cases, save your life. This article discusses the signs that you should get a colonoscopy.

An illustration with information about when to get a colonoscopy

Illustration by Jessica Olah for Verywell Health

When You Should Get a Colonoscopy

Colorectal cancer (cancer affecting the colon and rectum) is the third most common cancer in the United States. In 2021, an estimated 104,270 new cases of colon cancer were diagnosed.

In recent years, there’s been a surge of new colon cancer cases in younger adults. Since the 1990s, the rate of colorectal cancer has more than doubled in people younger than 50. For these reasons, it's important to follow colon cancer screening guidelines.

When you first get a colonoscopy and how often you need follow-up tests will depend on your age and personal risk factors. Your healthcare provider might also recommend the test if you have certain gastrointestinal symptoms.


The U.S. Preventive Services Task Force (USPSTF) recommends that adults between the ages of 45 and 75 be screened for colorectal cancer. The task force recommends that adults between ages 76 and 85 should ask their healthcare providers if they should undergo screening.

The USPSTF guidelines state that most people with an average risk for colorectal cancer should begin screening after they turn 45 years of age.

You may be at an increased risk for colon cancer if you have:

In these cases, your healthcare provider might recommend that you undergo screening at an earlier age and more often than average.

Types of Screening

The USPSTF recommends several types of screening methods, including:

Your provider can help you determine which method is most suitable for your situation.

Family History

When developing a colon cancer screening plan, your family history is an essential factor to consider. About 1 in every 4 people with colorectal cancer has a family history of the cancer.

Those with a family history of cancer are typically screened either at age 40 or 10 years before the youngest case in their immediate family (whichever comes first).

Gastrointestinal Symptoms

Your provider may recommend that you have a colonoscopy if you develop signs or symptoms of colon cancer, which may include:

  • Changes in bowel habits, such as diarrhea or constipation
  • Rectal bleeding or blood in the stool
  • Changes in the appearance of stool
  • Abdominal pain or cramping
  • Weakness or fatigue
  • Unexplained weight loss 

Symptoms Aren't Always Obvious

Many times, colon cancer doesn't cause symptoms until it has spread. That's why screening with a colonoscopy is so important. Spotting this cancer early might make it easier to treat. Additionally, your healthcare provider may be able to prevent colon cancer by removing precancerous polyps during a colonoscopy procedure.

Potential Causes of Digestive Issues

Digestive symptoms don't usually mean cancer. Many of the symptoms of colon cancer are also problems associated with other, common medical conditions.

Infection or Illness

Infections that attack your body can cause symptoms, such as vomiting, diarrhea, stomach cramps, or pain in the abdomen or rectum.


Hemorrhoids are swollen veins inside the rectum or outside the anus. They can cause pain, itching, and rectal bleeding.

Inflammatory Bowel Diseases

IBD include Crohn’s disease and ulcerative colitis. These two conditions cause chronic inflammation in the gastrointestinal tract. They can trigger symptoms that mimic those of colon cancer, such as abdominal pain, diarrhea, rectal bleeding, bloody stools, weight loss, and fatigue.

IBD and Colon Cancer

Studies show that people with inflammatory bowel disease are at a significantly increased risk of developing colon cancer. If you have Crohn's disease or ulcerative colitis, you should be especially vigilant about screening. Having inflammatory bowel disease also raises the risk of melanoma, a serious type of skin cancer.

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common condition that affects the digestive system. If you have IBS, you might experience diarrhea, constipation, gas, or bloating. However, IBS doesn’t damage your digestive tract or put you at risk for colon cancer.

What to Discuss With Your Healthcare Provider

If your healthcare provider suspects you have colon cancer, you may undergo tests or different types of exams.

Medical History

It's important to let your healthcare provider know of your entire medical history, especially if you've ever had cancer before.

Certain treatments, such as radiation to the abdomen or pelvic area, may put you at an increased risk for colon cancer.

Laboratory Tests

A complete blood count (CBC), liver enzyme test, or a tumor marker blood test may help your provider determine if you have colon cancer.

Imaging Tests

Your healthcare provider might order certain imaging tests to identify colon cancer or learn more about a suspicious area. These may include:

Colonoscopy Alternatives

Some tests may serve as alternatives to a colonoscopy. These include:

  • Computed tomography (CT) colonography: This screening method, known as a “virtual colonoscopy,” is a special type of X-ray used to examine the colon. It may be an option for some people who can’t tolerate the anesthesia needed for a standard colonoscopy. A skilled radiologist is required to interpret the results of this test.
  • Sigmoidoscopy: With a sigmoidoscopy, a flexible, lighted tube is inserted into the rectum and only the lower part of the colon to check for cancer and other abnormalities.
  • Stool DNA tests: These analyze the DNA in an individual’s stool sample to identify cancer.
  • Fecal occult blood test (FOBT): These look for blood in a person’s stool.
  • Double-contrast barium enema (DCBE): With this test, a person uses an enema containing barium to coat the colon and rectum. This allows clinicians to see the colon and rectum more clearly in a series of X-rays that are then taken.

You should always talk to your healthcare provider when deciding on the best screening technique.

Insurance and Medicare Coverage

Most health insurance and Medicare plans help cover colon cancer screenings for people who qualify. Some plans will pay for the procedure completely. Check with your insurance company to find out what benefits are included.


A colonoscopy is a test that provides a view of the colon. In addition to diagnosing many medical conditions, this procedure can help detect colon cancer or precancerous lesions.

Screening time and frequency will depend on your age, your personal medical history, and your family’s medical history. Your healthcare provider might also recommend a colonoscopy if you are experiencing certain symptoms of colon cancer, such as abdominal pain, diarrhea, bloody stool, or other issues.

A Word From Verywell

A colonoscopy can be a lifesaving screening tool. Don’t wait to have this test if you’re due for it or your healthcare provider recommends the procedure. Some people avoid having a colonoscopy out of embarrassment. However, delaying screening can increase the odds that potential cancer will develop and spread. Talk to your provider if you have any concerns about the procedure.

Frequently Asked Questions

  • On which side of the body do you feel colon pain?

    Colon cancer pain is typically described as vague abdominal pain. The exact site of the pain will vary, depending on where the cancer is located. For instance, if the cancer spreads to your liver, you might feel pain in your upper-right abdomen.

  • Does getting a colonoscopy hurt?

    Many people worry that a colonoscopy will hurt, but the procedure typically causes minimal or no discomfort. You will be sedated and won't feel what's happening.

  • How long does it take to recover from a colonoscopy?

    The colonoscopy itself doesn't require any recovery time, but you may experience drowsiness from the anesthesia. You also might feel a little bloated or pass gas after the procedure. It usually takes about a day for you to feel back to normal.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. American Cancer Society. Key statistics for colorectal cancer.

  2. National Cancer Institute. Why is colorectal cancer rising rapidly among young adults?.

  3. Centers for Disease Control and Prevention. What should I know about screening?

  4. Colorectal Cancer Alliance. Family history and hereditary colorectal cancer.

  5. Centers for Disease Control and Prevention (CDC). Know the signs and symptoms of an infection.

  6. Stidham RW, Higgins PDR. Colorectal cancer in inflammatory bowel diseaseClin Colon Rectal Surg. 2018;31(3):168-178. doi:10.1055/s-0037-1602237

  7. Cleveland Clinic. Irritable bowel syndrome (IBS).

  8. American Cancer Society. Do I have colorectal cancer? Signs, symptoms and work-up.