Colon Polyps: Complete Guide to Symptoms, Causes, and Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: September 2026
A colon polyp is a small clump of cells that forms on the lining of the colon. Most are harmless, but over time some precancerous polyps — mainly adenomas and serrated lesions — can turn into colorectal cancer. Because polyps usually cause no symptoms, regular screening is essential: adults 45 and older should be screened regularly, and precancerous polyps found early can usually be removed safely and completely during a colonoscopy.
Quick Answer
What it is: A small clump of cells on the lining of the colon. Most polyps are harmless, but precancerous kinds — adenomas and serrated lesions — can turn into colorectal cancer over many years.
Symptoms: Most people have no symptoms at all, which is why polyps are usually found during routine colorectal cancer screening rather than because of symptoms.
Screening: Regular screening starts at age 45, or younger if medical conditions or family history raise your risk.
Removal: During a colonoscopy, polyps can be found and removed at the same time — removing them prevents them from growing larger or becoming cancerous.
Follow-up: The repeat colonoscopy schedule depends on how many polyps were found, how large they were, and what type they were — from 7 to 10 years down to as soon as 6 months to a year.
What Are Colon Polyps?
A colon polyp is a small clump of cells that forms on the lining of the colon. Most colon polyps are harmless. But over time, some colon polyps can turn into colorectal cancer, which can be deadly when found in its later stages.
Anyone can develop colon polyps, and your risk increases as you age. Colon polyps don’t usually cause symptoms, which is why screening tests are so important. Colon polyps found early can usually be taken out safely and completely, and regular screening is the best prevention for colorectal cancer.
The most common type of precancerous polyp is an adenomatous polyp, often called an adenoma. Healthcare professionals recommend removing adenomas to prevent them from growing larger or becoming cancerous.
Types of Colon Polyps
Medical professionals classify colon polyps into two groups: nonneoplastic and neoplastic. Nonneoplastic polyps are generally harmless and rarely turn into cancer. Neoplastic polyps are considered precancerous, meaning they can turn into cancer if they are not taken out.
Group | Types | Cancer Risk |
Nonneoplastic (noncancerous) | Hyperplastic polyps — very common, especially in the lower colon and rectum, usually small, almost never turn into cancer. Inflammatory polyps (pseudopolyps) — occur with inflammatory bowel disease such as Crohn’s disease or ulcerative colitis; they don’t turn into cancer but signal long-term inflammation. Hamartomatous polyps — disorganized but regular tissue; a single polyp in a child is usually harmless, but many polyps increase cancer risk. | Generally harmless |
Neoplastic (precancerous) | Adenomas: tubular adenomas (most common, lowest risk), tubulovillous adenomas (higher risk), villous adenomas (least common, most likely to become cancer, especially when large). Serrated polyps: sessile serrated lesions (flat, often in the right colon, hard to detect, may become cancer especially if large) and traditional serrated adenomas (rare, usually in the left colon, clearly precancerous). | Can turn into cancer if not removed |
Most colorectal cancers begin in an adenoma or serrated lesion that has been present for many years. In general, the larger the precancerous polyp, the greater the risk that it will become cancerous.
What Are the Symptoms of Colon Polyps?
Most people with colon polyps do not have any symptoms, which is why screening tests are so important. Colon polyps are often found as part of routine colorectal cancer screening.
When symptoms do occur, they can include changes in bowel habits, such as constipation or diarrhea that lasts longer than a week, which may mean the presence of a larger colon polyp or cancer. Changes in stool color can occur — blood can show up as red streaks or make stool appear black, though foods, medicines, or supplements can also change color. An increased amount of mucus in stool warrants a conversation with a healthcare professional. Bleeding from polyps can happen slowly over time without visible blood, and chronic bleeding may lead to iron deficiency anemia, which can cause tiredness and shortness of breath. A large colon polyp or cancer can block part of the bowel, leading to cramping and belly pain. And rectal bleeding can be a sign of colon polyps, cancer, or other conditions such as hemorrhoids.
What Causes Colon Polyps?
Experts haven’t found a single cause for colon polyps. They form when the usual process of cell growth and repair in the colon goes off track. Instead of replacing old cells in an orderly way, the body makes extra cells, which build up and form a polyp on the smooth lining of the intestine. Polyps can grow anywhere in the large intestine, including the colon and rectum.
When polyps grow in the rectum, they are called rectal polyps. The rectum is the lower part of the colon, so rectal polyps are simply a type of colon polyp.
What Increases Your Risk?
Factors that might increase the risk of colon polyps or cancer include age, certain intestinal conditions, family history, personal history, lifestyle factors, and diabetes.
Risk Factor | How It Raises Risk |
Age | Most people with colon polyps are 45 or older |
Intestinal conditions | Inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease, raises the overall risk of colorectal cancer |
Family history | A parent, sibling, or child with advanced colon polyps (10 mm or larger) increases your risk; more affected relatives means even greater risk |
Personal history | Previous polyps are a risk factor for forming new polyps |
Smoking and excess alcohol | Three or more alcoholic drinks a day increases risk; alcohol combined with smoking also appears to increase risk |
Diabetes | Diabetes increases polyp risk by 50% among all age groups |
Weight and lifestyle | Risk increases for people who are overweight, don’t exercise regularly, and eat a less healthy diet |
Race | In the U.S., Black people have a higher risk of developing colorectal cancer |
Hereditary Polyp Syndromes
Rarely, people inherit gene changes that cause colon polyps to form and increase the risk of colorectal cancer. Lynch syndrome, also called hereditary nonpolyposis colorectal cancer, may cause relatively few polyps, but those polyps can quickly become cancerous — it is the most common inherited form of increased colon cancer risk. Familial adenomatous polyposis (FAP) is a rare condition that results in hundreds or even thousands of polyps in teenagers or young adults; untreated, the risk of colon cancer is nearly 100%, usually before age 40. MUTYH-associated polyposis (MAP) is similar to FAP, caused by changes in the MUTYH gene. Peutz-Jeghers syndrome usually begins with freckles all over the body, including the lips, gums, and feet, followed by polyps throughout the intestines. Juvenile polyposis syndrome is most common in children ages 1 to 7. Serrated polyposis syndrome is most often not inherited and is defined by a history of multiple serrated lesions.
When Should You See a Doctor?
See a healthcare professional if you have belly pain, blood in the stool, a change in bowel habits that lasts longer than a week, or weight loss that happens without trying.
You should be screened regularly for colorectal cancer if you are age 45 or older, or if you are younger than 45 and have medical conditions or family history that increase your risk of colorectal cancer.
How Are Colon Polyps Diagnosed?
Screening tests are important for finding polyps before they become cancerous. These tests also can help find colorectal cancer in its early stages, when you have a good chance of recovery.
Screening Test | How It Works |
Colonoscopy | A small tube with a light and camera is inserted through the rectum to examine the entire colon. Polyps usually appear as bumps or slightly raised spots on an otherwise smooth lining, and can be removed or biopsied during the exam. |
Virtual colonoscopy | A CT scan views the colon using the same bowel preparation as a colonoscopy. If a polyp is found, a colonoscopy is needed to examine and remove it. |
Flexible sigmoidoscopy | Examines just the last third of the colon. Some polyps and cancers may not be found, so this test is repeated more often or used with a yearly stool-based test. |
Stool-based tests | One test checks for blood in the stool and is repeated every year. Another checks for blood and tumor markers and is repeated every three years. Positive results lead to a colonoscopy soon afterward. |
Blood-based test | An FDA-approved blood screen for colon cancer, repeated every three years. If positive, a colonoscopy is recommended to check for colon cancer. |
How Are Colon Polyps Treated?
A healthcare professional is likely to take out all polyps found during a bowel exam. Options for removal include polypectomy, minimally invasive surgery, and total proctocolectomy.
During a colonoscopy, very small polyps may be removed with forceps, and small to medium polyps are usually removed with a wire loop called a snare. Sometimes an electric current is applied to cut the polyp and prevent bleeding. Removing polyps prevents them from having the chance to grow into colorectal cancer.
Polyps that are too large or can’t be removed safely during colonoscopy are usually removed surgically, often by placing an instrument called a laparoscope into the abdomen to remove the part of the bowel with the polyp. If you have a rare inherited syndrome such as FAP, you may need surgery to remove your colon and rectum — a total proctocolectomy — which can protect you from getting colorectal cancer.
A pathologist studies the polyp tissue under a microscope to determine what type of polyp you have.
Follow-Up Care
If you have had an adenomatous polyp or a serrated lesion, you are at increased risk of colorectal cancer. The level of risk depends on the size, number, and characteristics of the polyps that were taken out. A healthcare professional is likely to recommend repeating a colonoscopy based on what was found.
Polyps Found and Removed | Recommended Repeat Colonoscopy |
One or two small adenomas | In 7 to 10 years |
Three or four adenomas | In 3 to 5 years |
5 to 10 adenomas, adenomas larger than 10 mm, or certain types | In 3 years |
More than 10 adenomas, a very large adenoma, or an adenoma removed in pieces | In 6 months to one year |
The follow-up schedule for serrated lesions is like that for adenomas.
How Should You Prepare for a Colonoscopy?
It’s very important to fully clean out your colon before a colonoscopy. If stool remains in the colon and blocks the view of the colon wall, you will likely need another colonoscopy sooner than usual to make sure all polyps are found. After good colon preparation, stool should appear as clear liquid, possibly slightly yellow or green depending on the liquids used while preparing. If you have trouble with your colon preparation or think you have not fully cleaned out your colon, tell the health professional before beginning the exam.
If you take medicines that affect bleeding, such as aspirin or medicines used for heart disease or blood clots, tell your healthcare team. Do not stop taking any medicines on your own — your care team advises whether to keep taking them or pause them before the colonoscopy, and how and when to start taking them again.
Can Colon Polyps Be Prevented?
The risk of colon polyps and colorectal cancer may be greatly reduced by having regular screenings. Certain lifestyle changes also can help: include plenty of fruits, vegetables, and whole grains in your diet and reduce fat intake; limit alcohol and quit all tobacco use; stay physically active and keep a healthy body weight.
If you have a family history of colon polyps, talk with a healthcare professional. If you have a personal history of 10 or more neoplastic polyps, consider having genetic counseling. If you’ve been diagnosed with a hereditary disorder that causes colon polyps, you’ll usually need regular colonoscopies starting in young adulthood.
Preparing for Your Appointment
You may be referred to a healthcare professional who specializes in digestive diseases, called a gastroenterologist. Be aware of anything you need to do ahead of time, such as not eating solid food on the day before your appointment. Write down your symptoms, including any that may not seem related to the reason you scheduled the appointment. Make a list of all your medicines, vitamins, and supplements, plus key medical and personal information. Ask a relative or friend to go with you, and write down questions to ask.
Questions to ask include: What’s the most likely cause of my symptoms? What kinds of tests do I need, and do these tests require any special preparation? What treatments are available? What are the chances these polyps are cancerous? Is it possible that I have a genetic condition leading to colon polyps? What kind of follow-up testing do I need? Should I remove or add any foods to my diet? I have other health conditions — how can I best manage these together?
Conclusion
Colon polyps are small clumps of cells on the colon lining that are usually silent — most people never feel them. That silence is exactly why screening matters: while most polyps are harmless, the precancerous adenomas and serrated lesions that sit undetected for years are where most colorectal cancers begin, and the larger the precancerous polyp, the greater the cancer risk. Screening typically starts at age 45, and a colonoscopy offers both detection and treatment in one procedure — polyps can be removed on the spot, often with a snare or forceps. After removal, your follow-up colonoscopy schedule is set by how many polyps were found, how large they were, and what type they were, ranging from 7 to 10 years down to as soon as 6 months to one year.
If you are 45 or older and haven’t been screened for colorectal cancer, talk with your healthcare professional about scheduling a screening. If you’ve noticed blood in your stool, belly pain, a bowel-habit change lasting longer than a week, or unexplained weight loss, make an appointment promptly.
Frequently Asked Questions
What is a colon polyp?
A colon polyp is a small clump of cells that forms on the lining of the colon. Most are harmless, but some can turn into colorectal cancer over time.
Are colon polyps dangerous?
Most polyps are harmless, but precancerous types — adenomatous polyps (adenomas) and serrated lesions — can become colorectal cancer if not removed. Most colorectal cancers begin in an adenoma or serrated lesion present for many years.
What are the symptoms?
Most people have no symptoms at all. When symptoms occur, they can include belly pain, blood in the stool, changes in bowel habits lasting longer than a week, weight loss without trying, iron deficiency anemia, or increased mucus in stool.
When should I start screening?
You should be screened regularly for colorectal cancer if you are age 45 or older, or younger than 45 with medical conditions or family history that increase your risk.
How are polyps found?
Through screening tests: colonoscopy (examines the entire colon and can remove polyps during the exam), virtual colonoscopy (CT scan), flexible sigmoidoscopy (last third of the colon), stool-based tests (yearly or every three years), or an FDA-approved blood-based test (every three years). Positive non-colonoscopy results lead to a colonoscopy.
How are polyps removed?
Small polyps are removed with forceps during a colonoscopy; small to medium polyps are usually removed with a wire loop called a snare, sometimes with an electric current to prevent bleeding. Larger or unsafe-to-remove polyps may require surgery.
How often will I need another colonoscopy after removal?
It depends on what was found: one or two small adenomas — in 7 to 10 years; three or four adenomas — in 3 to 5 years; 5 to 10 adenomas, or adenomas larger than 10 mm — in 3 years; more than 10 adenomas or a very large or piecemeal-removed adenoma — in 6 months to one year.
Can colon polyps be prevented?
Regular screening greatly reduces risk, along with lifestyle changes: plenty of fruits, vegetables, and whole grains; less fat; limiting alcohol; quitting tobacco; staying active; and keeping a healthy weight. High-risk individuals may also benefit from genetic counseling.
External References
Health information, not medical advice. This article is for general education and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your own health, and seek emergency care for urgent symptoms.
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