What To Expect From Your Colonoscopy: Frequently Asked Questions & A Timeline

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    You may be anxious about your upcoming colonoscopy appointment with concerns about the procedure itself and the results you may receive. You are not alone. The majority of patients undergoing a colonoscopy will have anxiety of some sort, ranging from anxiousness about the bowel preparation, concerns about sedation and pain of the procedure, and fear of a cancer diagnosis. 

    Anxiety and fears about your upcoming colonoscopy are natural and you should discuss any of these with your healthcare team before your procedure. If you are concerned about feeling embarrassed during the colonoscopy or that you will be in a lot of pain, discuss these anxieties with your physician. Be open about any and all concerns you have about your procedure whenever these feelings arise. Many people experience anxiety the day of the colonoscopy and discussing this feeling with your healthcare team will allow them to approach you with the care, sensitivity and respect you deserve. Informing yourself about the details of the procedure well in advance can also help ease your anxiety. With this knowledge, you will be prepared to ask your physician questions and become informed about what to expect. 

    This article is intended to answer some of the most common questions about  what to expect from your colonoscopy and provide you with a step-by-step account of the appointment.  

    Why is My Doctor Recommending a Colonoscopy? 


    A colonoscopy is recommended by physicians for several reasons. These include:

    • Screening procedure to detect the presence of cancerous tissue or colorectal cancer
    • Screening procedure to detect the presence of abnormal tissue or polyps
    • Follow-up due to history of polyps to see if there are new polyps to remove
    • Diagnose the source of abdominal and intestinal disturbances, including abdominal pain, abrupt changes in bowel movements, and rectal bleeding 

    What Tools Will the Doctor Use During a Colonoscopy, How Long Does It Take, and What Is He/She Looking For?


    A colonoscopy is a procedure that allows your physician to closely examine the lining of your large intestine or colon using a colonoscope. A colonoscope is a long, flexible tube that is inserted into the rectum to detect abnormalities in the lining of the lower intestinal tract (colon and rectum), The tube has a very small camera on the tip of the tube that provides a clear view of the colon.

    During the procedure, patients are typically sedated and experience little to no pain or discomfort for the examination. Following sedation, the patient will be asked to lie down on one side (usually the left) and the physician will insert the scope into the patient’s rectum. The procedure can take from 15-60 minutes but may be longer if the physician finds a polyp and needs to remove the abnormal tissue.  

    Polyp – a growth on the inner lining of the colon or rectum. Polyps can have different shapes (flat, slightly raised, stalk-like) and can be precancerous or benign. Two-thirds of all polyps are adenomas, the precancerous type.  

    The colonoscope’s tube is narrow but can fit small tools that allow the gastroenterologist to remove small polyps, administer medication, and stop bleeding if necessary. Rarely, a complication occurs which requires the procedure to take more time. 

    What is the Check-In Procedure Like? 


    Upon arrival, you will check in with admissions. Your healthcare staff will make sure that you have prepared for someone to take you home after the procedure. You can take public transportation, but you will need an adult who can accompany you to your home. 

    Once you are in the preparation room, you will be asked to change into a gown and be prepped for the colonoscopy. This typically involves the following:

    1. You will be asked to sign consent forms for the procedure,
    2. Your vitals will be taken, including temperature, blood pressure, and heart rate. 
    3. A nurse will place an I.V. into your arm.
    4. Your gastroenterologist will explain the procedure to you including describing the risks involved with colonoscopy.
    5. Your anesthesiologist will describe to you how you will be sedated and how you will feel when you wake up.
    6. You will be wheeled to the room where your colonoscopy takes place.  

    How long does the colonoscopy procedure take?


    The procedure typically takes from 15-60 minutes, but expect the appointment to take from 2 to 3 hours for preparation, waiting, and recovery time. You may also spend more time in the examination room if your physician needs to remove polyps and send the tissue to the lab for analysis.  

    What sedation will my anesthesiologist use?


    The sedation for a colonoscopy ranges from mild sedation to deep anesthesia during which you will fall asleep and awaken quickly. Many clinics will advise moderate sedation so you are conscious but not experience pain.Types of sedation commonly used during a colonoscopy include:

    Light sedation. This minimal type of sedation helps you to relax and greatly reduces the pain and discomfort of the procedure while keeping you awake. Common light sedation drugs are opioids and benzodiazepines. An advantage of minimal sedation is you can respond to questions and follow directions for your gastroenterologist. You may feel pain and discomfort if you are lightly sedated. 

    Moderate sedation. In this case, a greater amount of sedation drug (usually benzodiazepine or an opioid) is used to the point you will not remember the procedure and you may fall completely asleep. You have a lower risk of slowed breathing and low blood pressure with moderate sedation but you may feel some pain and discomfort. 

    Deep sedation. Propofol is a common non-opioid sedative drug for this type of sedation. You will not be completely unconscious, but you will sleep through the procedure with no memory of it upon awakening. There is a risk for low blood pressure and slower breathing when you are deeply sedated. 

    General anesthesia. Typically not used for a colonoscopy, general anesthesia is used for people who have a high risk for vomiting during a procedure or have airway abnormalities. Anesthetics are generally inhaled and require that you to have a breathing tube and ventilator placed during the procedure. 

    Your physician will ask you if you have any allergies to sedation drugs and discuss your options for level of sedation. There are risks and side effects associated with each drug and talk to your physician about these associated reactions before your procedure. Sedation drugs that are commonly used include:

    • Diazepam
    • Diphenhydramine
    • Fentanyl
    • Meperidine
    • Midazolam
    • Propofol
    • Promethazine 

    When you wake up from your colonoscopy, expect to feel quite sleepy and disoriented. You may have a headache or feel nauseous. Be sure to tell your anesthesiologist about any symptoms you are experiencing to make sure you are not having an adverse reaction.  

    What happens when I am sedated during a Colonoscopy?


    During the procedure, you will be asked to lay down on your left side. To get a clear image of the lining of your colon and rectum, your gastroenterologist will use a colonoscope. The colonoscope is the size of a finger and is inserted into the rectum while you are sedated. Sedation usually includes a light anesthesia and pain medication to help the patient relax and feel comfortable. While you are lying on the table, your gastroenterologist slowly guides the colonoscope throughout the colon. Your colon will be inflated by the scope during the procedure to give a clear view of the entire tube. You may be moved around so your gastroenterologist to adjust the scope for better views of the lining. When the scope reaches the opening of the small intestine your physician will slowly withdraw it while re-examining the intestinal lining. 

    What Happens During A Colonoscopy Procedure:  Step-by-Step


    1. Your nurse will place an intravenous (IV) needle in a vein in your arm where your anesthesia is given.
    2. The surgical staff monitors your vital signs and makes sure you are comfortable. 
    3. You will lie on your side on the table.
    4. The gastroenterologist inserts the scope and performs colonoscopy. 
    5. If your physician finds a polyp or abnormal tissue it will be removed and sent to the lab for testing. 
    6. If bleeding occurs, your physician will pass special tools through the tube to stop the bleeding with an electrical probe or by medication.  

    What is the timeline for colonoscopy: 2-3 hours 


    30 minutes before colonoscopy

    You will be asked to change into a gown and get your vitals taken. A member of the medical staff will get an IV started. Your gastroenterologist and your anesthesiologist will tell you what is happening during your procedure and discuss any questions and concerns you have.  

    5-10 minutes before the procedure 

    In the examination room, you will be asked to lie down on your side. Next, you will be connected to the equipment that monitors your heart rate, blood pressure, and levels of oxygen. You may receive oxygen through your nose. Your sedation drugs will be given to you right before your colonoscopy.  

    Colonoscopy: 30-60 minutes

    Your gastroenterologist inserts the colonoscope into your rectum. This instrument sends video images to a monitor so your physician has a clear view of your intestinal lining. Your physician will remove any polyps found or take small pieces of abnormal tissue to be sent to a pathology lab for analysis. 

    Recovery: 30-60 minutes

    Once your IV is removed, the effects of the sedation can last up to 30 minutes. Your medical team will monitor your vitals to make sure you are stable. Your physician will check in on you to tell you how the procedure went, including if polyps or abnormal tissue were found.  

    You may feel bloated or gaseous after the procedure. You may also experience some light bleeding if your physician removed polyps or took a sample of abnormal tissue for laboratory analysis. Contact your physician or seek immediate medical attention if you experience any of the following symptoms:

    • Severe abdominal pain
    • Lightheadedness or fainting spell
    • Moderate to heavy bleeding from the rectum
    • Fever 


    American Society of Anesthesiologists. (2021). Colonoscopy. Retrieved from ASA: 

    Barber, T. (2020, July 20). How long does a colonoscopy take? Retrieved from Colorectal Cancer Alliance: 

    Beaumont Health. (2021). Colonoscopy procedure: What to do before and after. Retrieved from Beautmont: 

    National Institute of Diabetes and Digestive and Kidney Diseases. (2013, September). Colonoscopy. NIH Publication No. 13-4331. Retrieved from NIH:

    Stanborough, R. J. (2020, January 03). Does a colonoscopy hurt? Retrieved from Healthline: