Colonoscopy is usually recommended when your doctor wants to investigate intestinal signs and symptoms, screen for colon cancer, check for polyps or treat some underlying issue. When done timely, colonoscopy can detect cancers while they are treatable and small growths before they turn cancerous. The highly trained and skilled gastroenterologists at Manhattan Gastroenterology use advanced technological equipment to determine what is happening inside and evaluate your lower GI symptoms. The top-rated specialists perform diagnostic colonoscopies to reduce the risk of colorectal cancer, identify polyps, and detect colon cancer in its earliest stage. Preparing for your colonoscopy correctly and following the specialist’s instructions carefully can help diagnose, manage, and treat various GI problems.

What Is a Colonoscopy?


A colonoscopy is an exam that views the inside of the colon, also known as the large intestine and rectum, using a tool called a colonoscope. The colonoscope has a tiny camera attached to a flexible tube that can reach the length of the colon.

A colonoscopy is one of the most effective ways to spot or help prevent colon cancer. It can spot small colon cancers while they are treatable and before they spread to other body parts. It can also detect and remove polyps, small growths that can develop into colon cancer if not detected timely. Many people fear the process because they do not know what goes on during the colonoscopy and are afraid of what they will have to go through to prepare for it.

Prep Instructions for Colonoscopy

Preparing for colonoscopy, learning how it will take place and how it can ease things later will help you go through the process. The doctor will guide you about the procedure and provide detailed information on what colonoscopy is all about and what happens during the process. The colon has to be empty and clean for your doctor to get a proper look at it. To make that happen, you will be asked to fast and use strong laxatives beforehand. It may be inconvenient and somewhat unpleasant, but it is just for a few hours and will be over before you know it.

You can make the process of colonoscopy easy by getting ready for it and following the preparation instructions provided by your hospital or doctor.

Getting Ready for a Colonoscopy

There are various options for cleansing your bowels in preparation for colonoscopy. Different medical centers recommend ways to prepare for the procedure. It is essential to follow the doctor’s guidelines to ensure everything goes without any trouble.

Follow the #1 prep instructions for your colonoscopy below.

What to do

You must stop taking or eating the following 7 days before the procedure:

  • Iron supplements
  • Fiber supplements such as Metamucil, Citrucel, and Fiberall
  • Nuts, seeds, popcorn, or corn or granola with dried foods and raisins

Tell your doctor if you are:

  • Diabetic
  • Pregnant
  • Take Coumadin, Warfarin, Plavix, or any other anti-coagulation therapy
  • Have an artificial heart valve, internal cardiac defibrillator (ICD), prior history of heart valve infection, or require antibiotics before medical procedures
  • Going through dialysis or have chronic kidney disease and taking medications for your condition

Continue taking all your medications unless directed otherwise by the doctor. They doctor may adjust the dosages or ask you to stop taking the medications temporarily.

On the day of the procedure

Your doctor may allow you to eat one meal before 11 AM but only from the following list of foods:
• Boiled or poached egg
• Cottage cheese
• Plain yogurt without any granola or fruit chunks
• Chicken, turkey, or fish without skin
• White bread or toast without butter
• Plain tofu

If you have not been provided a food list, ask your doctor about what you can eat. After 11 AM, you will stick to clear liquid only. A clear liquid is one that you can see through. It should not contain anything blue, purple, or red.

These liquids can be taken up to 3 hours before the procedure. You must not eat solid foods.

Examples of clear liquids include:

  • Clear beef or chicken broth, such as bouillon cubes dissolved in water
  • Popsicles, except for red, purple, or blue
  • Coconut water (NOT coconut milk)
  • Strained fruit juice such as apple or white grape juice
  • Coffee and tea (without cream or dairy products)
  • Gatorade
  • Soft drinks
  • Kool-Aid
  • Jell-O

From 2 to 5 PM – You will be asked to prepare an 8.3 oz. bottle of Miralax or Gavilax with 64 ounces of orange, green, or yellow Gatorade, Propel Water, Vitamin Water, coconut water, or Smartwater. You can make the solution one hour before if you want to drink it chilled. Once the mixture is ready, drink an 8-ounce glass every 10 to 20 minutes until you have drunk half of it.

As you drink the mixture, you may feel nauseous or have an urge to use the bathroom. It is better that you stay close to the toilet while consuming this mixture so that you can reach the bathroom timely in case of an emergency. If you start feeling nauseous, stop drinking the solution for a while until the feeling passes, then resume. About 2 hours after you have begun drinking the prep solution, you should start having bowel movements.

It is important to note that if your bowel movements do not start 2 hours after you have begun drinking your prep solution, continue drinking the other half of the solution to stimulate the bowel movement.

The day/morning of the procedure

On the day or morning of the procedure, drink the remaining solution of Miralax or Gavilax mixture after every 10 to 20 minutes until it is all gone. If you had already finished the entire 64 ounces the day before because your prep was not working well, get a 10 oz. bottle of magnesium citrate at this point.

Stop drinking all liquids 3 hours before the procedure.

After you have consumed the Miralax/Gavilax mixture, take two Simethicone or Gas-X anti-gas tablets. These tablets would be the last thing you take orally before the procedure, except your usual medications with a sip of water. You should be done with all drinking and medications 3 hours before the scheduled colonoscopy. Do not eat or drink anything else. Consult your doctor if you are not feeling well. It would be best if you had a clear and yellow stool.

Significance of good prep

Like any other medical procedure, good prep for a colonoscopy is also essential. It would not be wrong to say that prep is one of the most crucial parts of your colonoscopy. Without good prep and properly empty and clean bowels, your gastroenterologist will not be able to see your colon. It could lead to missing a polyp or rescheduling your colonoscopy.

Discuss the significance of colonoscopy and its prep with your gastroenterologist to ensure the procedure goes smoothly and painlessly.

Important Points to Note

Risk factors of colonoscopy

Even though colonoscopy is a standard medical procedure, it also carries some risks like other medical procedures. These problems do not happen often, but it is vital to know about them and be prepared. Risk factors include:

  • In rare cases, the instrument may tear the wall of the colon. This may require corrective surgery.
  • There may be adverse drug reactions or heart/breathing complications.
  • In rare instances, bleeding may occur. It usually happens when tissue or polyps are removed. You may require additional medical care and have to stay in the hospital if a transfusion or surgery is needed.

You must not come for the procedure alone. It is necessary to bring someone who will meet you inside the recovery area after the process is over and drives you home. Even though colonoscopy is not invasive, having someone to accompany you or care for you at home helps.

Preparing for colonoscopy is difficult and takes a lot of time. Still, it is a necessary step to protect your gastrointestinal health and get yourself checked internally for any underlying condition. Preparation plays a very crucial role in colonoscopy. If you prepare well, the doctor can see what they need, and the procedure will proceed smoothly. The board-certified and experienced gastroenterologists at Manhattan Gastroenterology help you understand the need for colonoscopy and how it can prove beneficial for the diagnosis and treatment of gastric issues you may be having. The expert doctors perform screening colonoscopy to manage your health concerns and help you feel better within no time.

Updated on Sep 1, 2023 by Dr. Shawn Khodadadian (Gastroenterologist) of Manhattan Gastroenterology