What to Expect at Your Colonoscopy Appointment

What a colonoscopy is and why your doctor ordered one

A colonoscopy is a procedure where a gastroenterologist (a doctor who specializes in the digestive system) uses a thin, flexible tube with a camera on the end to look inside your colon and rectum. The tube is called a colonoscope. Your doctor can see the entire length of your large intestine on a monitor and check for polyps, inflammation, bleeding, or signs of cancer.

Doctors order colonoscopies for several reasons: to screen for colorectal cancer (usually starting at age 45 or 50, depending on your risk factors), to investigate symptoms like persistent diarrhea or blood in your stool, to remove polyps before they become cancerous, or to follow up on previous findings. If your doctor has recommended one, they believe the benefit of looking inside your colon outweighs the small risks involved.

Key Takeaways

• You will need to empty your colon completely before the procedure using a bowel prep — usually a strong laxative drink you take the day before — so the doctor can see clearly.
• The procedure itself takes 20 to 45 minutes, you will be sedated so you won't feel pain, and you can go home the same day but cannot drive for the rest of the day.
• Arrange a ride home before your appointment because the sedation will impair your ability to drive safely, even if you feel alert.
• Most colonoscopies find nothing serious, and if polyps are found and removed during the procedure, you may not need another colonoscopy for several years.
• Plan to take the full day off work — the prep the night before often disrupts sleep, and you cannot operate machinery or make important decisions the day of the procedure.

The bowel prep: what to drink and when

The most important part of a colonoscopy is the bowel prep, which happens at home the day before your appointment. Your doctor will send you instructions that specify exactly which prep solution to use — common ones include GoLYTELY, Miralax, or Suprep. These are prescription or over-the-counter laxatives that work by drawing water into your colon to flush out stool. You cannot skip this step; if your colon is not completely clean, the doctor cannot see the lining clearly and may miss polyps or other problems.

Most prep instructions tell you to start drinking the solution in the late afternoon or evening before your appointment. You will drink a large volume — typically 1 to 2 liters — over a few hours. The solution tastes unpleasant to most people (salty, medicinal, or artificially flavored), and it works quickly. You will have frequent, loose bowel movements for several hours. This is normal and necessary. Some people find it easier to drink the solution through a straw or to chill it beforehand.

Your doctor will also give you a list of foods and drinks to avoid starting a few days before the procedure. Generally, you stop eating solid food the day of the prep and stick to clear liquids only — water, broth, apple juice, black coffee or tea (no milk), and sports drinks. Avoid red, purple, or blue liquids because they can stain the colon and look like blood. Follow the instructions exactly; if you eat solid food or drink the wrong thing, you may have to reschedule.

What happens on the day of your appointment

Arrive 15 minutes early to check in. You will be taken to a pre-procedure area where a nurse will ask about your medical history, current medications, and allergies. Tell them about any blood thinners you take, any previous reactions to sedation, or any medical conditions like heart problems or sleep apnea. You will change into a hospital gown and an IV line will be placed in your arm so the doctor can give you sedation.

You will be moved to the procedure room, where the gastroenterologist and nursing staff will be waiting. The doctor will explain what they are about to do. You will lie on your left side on the procedure table. The doctor will apply lubricant to the colonoscope and gently insert it into your rectum. Once the sedation takes effect — which happens quickly — you will not remember the procedure. Most people describe waking up and being told it is already over.

During the procedure, the doctor looks at the lining of your colon on a monitor. If they see a polyp, they can remove it right away using a small tool passed through the colonoscope. Removing a polyp does not hurt because there are no pain nerves in the colon. If the doctor sees anything unusual, they may take a small tissue sample (a biopsy) to send to a lab. The entire procedure usually takes 20 to 45 minutes, though you will spend longer in the pre- and post-procedure areas.

Recovery and what you can do after

After the procedure, you will be moved to a recovery area where the sedation wears off over 30 to 60 minutes. A nurse will monitor your vital signs and make sure you are alert enough to go home. You may feel groggy, confused, or emotional — this is the sedation leaving your system and is completely normal. Do not be surprised if you do not remember parts of the procedure or the recovery period.

You cannot drive, operate machinery, or make important decisions for the rest of the day because the sedation impairs judgment and reaction time, even if you feel fine. This is not optional; it is a safety rule. You must have a responsible adult drive you home. If you do not have someone to pick you up, tell the clinic ahead of time — some facilities can arrange a medical transport service, though you may pay a fee.

You can resume eating and drinking as soon as you get home, though start with light foods like soup, crackers, or toast. You may feel bloated or have mild cramping from air the doctor pumped into your colon to see better — this passes within a few hours. If polyps were removed, you may see a small amount of blood in your stool for a day or two; this is normal. You can return to normal activities the next day.

What the results mean and when you will hear them

The doctor will give you a summary sheet before you leave that describes what they found. If nothing abnormal was seen, the sheet will say "normal colonoscopy" or "no polyps found." If polyps were removed, it will say how many and what size. If a biopsy was taken, those results come back from the lab in 3 to 7 days, and the doctor's office will call you with the findings.

If your colonoscopy was normal and you have no family history of colorectal cancer or other risk factors, you typically do not need another colonoscopy for 10 years. If small polyps were removed, the interval is usually 5 to 10 years. If larger polyps were found or if a biopsy showed precancerous changes, your doctor will recommend a follow-up colonoscopy in 1 to 3 years. These intervals are based on research about how fast polyps grow and when they are most likely to become cancer.

Medications and supplements to pause before your appointment

Tell your doctor about all medications and supplements you take, especially blood thinners like warfarin, apixaban, or dabigatran; aspirin; and nonsteroidal anti-inflammatory drugs like ibuprofen or naproxen. Depending on your condition and the reason for the colonoscopy, your doctor may ask you to stop these drugs a few days before the procedure to reduce bleeding risk, or they may tell you to keep taking them. Do not stop any medication on your own — wait for the doctor's instruction.

Iron supplements and some herbal supplements can also interfere with the bowel prep or the doctor's ability to see clearly. Bring a list of everything you take, including over-the-counter vitamins and herbal products, to your pre-procedure appointment. The nurse will review it and let you know if anything needs to be paused.

Possible complications and when to call the doctor

Colonoscopy is a safe procedure. Serious complications are rare — they occur in fewer than 1 in 1,000 procedures. The most common minor side effects are bloating, cramping, and mild bleeding from polyp removal, all of which resolve on their own within a day or two.

Call your doctor or go to an emergency room if you experience severe abdominal pain that does not go away, heavy rectal bleeding (more than a small amount), fever over 100.4°F, or signs of dehydration like extreme dizziness or fainting. These symptoms could indicate a rare complication like perforation (a tear in the colon wall) or infection, which need prompt medical attention. However, these complications are uncommon, and most people have no problems at all.

Frequently Asked Questions

Will I feel pain during the colonoscopy?

No. The sedation prevents you from feeling pain, and the colon has no pain nerves anyway. You may feel pressure or mild discomfort as the colonoscope moves through your colon, but you will be sedated and will not remember it. Some people feel mild cramping the next day from air left in the colon, which is normal and passes quickly.

What if I cannot finish the bowel prep because it tastes bad or makes me feel sick?

Tell your doctor or the clinic before your appointment. There are several different prep solutions available, and some taste better than others. Some people tolerate Miralax mixed with a sports drink better than the standard GoLYTELY solution. Your doctor can switch you to a different prep. If you vomit or cannot complete the prep, call the clinic — they may reschedule rather than proceed with an incomplete prep.

Can I take my regular medications the morning of the procedure?

It depends on the medication. Blood pressure medications and heart medications are usually taken with a small sip of water a few hours before the procedure. Diabetes medications are often held on the day of the procedure because you are fasting. Your doctor will give you specific instructions in your pre-procedure paperwork. If you are unsure, call the clinic the day before to confirm.

How long does it take to get results back?

The doctor will give you a summary of findings before you leave. If biopsies were taken, those results come back from the lab in 3 to 7 days, and the clinic will contact you. If nothing abnormal was found, you may not hear from the clinic again unless you call to ask — no news is good news.

What if the doctor finds cancer during the colonoscopy?

If the doctor sees something that looks like cancer, they will take a biopsy and send it to a pathologist for examination. The biopsy results come back in a few days. If cancer is confirmed, your doctor will refer you to an oncologist and discuss treatment options. However, colonoscopies are often used to find and remove polyps before they become cancer, which is why screening is so important.