Colonoscopy Preparation - Get Clean and Ready

Colonoscopy preparation is extremely important because if your bowel is not prepared properly for the test then the doctor will not be able to see if anything is wrong.

A colonoscopy test involves your doctor visually inspecting the inside of your bowel using a special flexible telescope/camera. Sometimes the doctor will look directly at the inside of your intestines but usually the pictures will be transmitted to a screen.

Imagine if your bowel is still full of poop; the doctor will not get to see much!

This article will take you through the different ways that your bowel can be cleaned out ready for the test.

You will be given instructions by your doctor which you should follow but the information here will let you know what to expect and tips on how to cope.

Colonoscopy Preparation - Diet or Laxatives?

The two main ways to clean out your bowel are either through following a special diet or by taking very strong laxatives. In practice many doctors recommend a combination of the two.

Colonoscopy Preparation - Do I Need To Plan Ahead?

If you have a colonoscopy examination coming up then my advice is to start preparing at least 5 days ahead.

If you start reducing what goes in then there will be less to come out! So work back from the day of the exam and gradually reduce the amount of fiber in your diet.

I was advised that I didn't need to do this as the strong laxative I was given would take care of everything but I wish with hindsight that I had ignored this piece of advice. I would not have been sitting on the toilet for quite so long and would not have suffered such a volume of diarrhea!

It has also been found that patients who rely on the laxative alone and do not adjust their diet do not always have a clean enough bowel. This can result in a waste of time for you and the doctor if they cannot see properly.

The instructions on some laxative products will say that no colonoscopy preparation diet is necessary but this does not always work out for the best.

If you normally suffer from constipation tell your doctor as they may want to prescribe a regular laxative for you to take 2 or 3 days before the test.

Clear your schedule completely the day before the examination because unfortunately you will need to be in the bathroom!

Arrange to have any children or elderly parents looked after. You won't be able to do it.

Which is the Best Colonoscopy Prep Diet?

The basic principle of the colonoscopy preparation diet is to do the opposite of what all the health professionals are always telling us to do.

So you know how you are always being told to eat more fruit and vegetables and to go for wholefoods like brown rice and wholemeal bread; well in the lead up to a colonoscopy everything must be white and bland!

The idea is to start cutting out fiber almost a week before and then gradually reduce the fiber to nothing and reduce the amount of solid food you are eating so that just before the test you are only having clear fluids.

By doing this your bowel will be nice and empty and the doctor will get a clear view of the intestinal lining.

This will make it much easier to for them to notice any abnormalities.

Which Foods Must Go and Which Can Stay?

The colonoscopy preparation diet should start at least 5 days before the test. 

At the beginning you can eat everything on the 'Eat List' below but as the test gets nearer cut out all fruits and vegetables.

Colonoscopy Preparation Diet - The Day Before

The day before the test and on the day of the test most doctors recommend only clear fluids.

A clear fluid is something you can see through and which has no bits. So cloudy does not qualify and neither does chicken noodle soup! Well, unless you strain out the chicken and the noodles. (You can eat the chicken and noodles up to day 2 before the test as long as there are no vegetables in your soup) You can have tea or coffee but it must be without milk. Clear bouillon, consomme, Oxo, Bovril, energy drinks, clear fruit juices and cordials qualify. Do not drink anything red or purple.

Sometimes you only have to start the clear fluid diet after lunch if your appointment is in the afternoon the next day.

Most doctors ask you to be nil by mouth for two hours before the test.

Colonoscopy Prep Diet Day 5-2 Before the Test



Colonoscopy Preparation - Duck ConsommeAs the Test Gets Nearer the Fluids Must Get Clearer



Clear broths, bouillon, consomme, strained soups
Hot chocolate
Clear fruit juices such as apple
Energy drinks
Carbonated drinks

Don't Eat


Vegetable juice
Fruit juices with pulp
Red or purple drinks
Thick soups
Soups with veg in


Colonoscopy Diet - MilkKeep it Plain; Feel the Gain


Smooth plain or flavored yogurt
Soya milk
Ice cream (no nuts or fruit or red)


Yogurt with fruit, nuts or seeds


Colonoscopy Preparation Diet - White BreadKeep it White!


Bread, rolls, bagels made with refined white flour
White pasta
Low fiber cereals
like puffed rice, rice crispies
White rice
Plain biscuits
Plain pancakes, waffles


Brown or wild rice
Whole grain, brown bread
Whole grain, high fiber cereals like granola and muesli


Colonoscopy Prep - Fruits Not AllowedSorry


Pears and apples soft canned or cooked
Melon honeydew or cantaloupe


Raw fruit
Red fruit
Dried fruit
Skin, seeds


Colonoscopy Diet - FriesYes You Can but Not Every Meal!


Cooked soft carrots
Cooked soft turnips
Cooked soft swede
Mashed, baked, boiled potatoes, fries (no skin)


No raw vegetables or salad
No skin or seeds
Peas, Beans
Onion, Leek
Brussel sprouts


Colonoscopy Preparation - Poached Fish FilletsYes it Really Does Have to be This Bland!


Chicken (well cooked and tender)


Tough meat
Red meat
Crispy fried meat or fish
Battered meat, seafood or fish


Colonoscopy Preparation - MayonnaiseMy Favorite but Go Easy!


Small amounts of


Fatty and fried foods
Fat attached to meat
Peanut butter


Colonoscopy Diet - Lentils Not AllowedNormally Good, Pre-Colonoscopy Bad




Dried beans and peas


Colonoscopy Prep - HoneySugar and Honey are Not Off the Menu


Jelly jam
Lemon juice
Ice lollies (not red)


Jam with fruit and seeds
Wholegrain mustard

I Am Worried About Not Eating Anything. What Can I Do?

The thought of not having anything but clear fluids for hours is very worrying for many people in our modern times when it is rare to be very far from food.

Be assured that not eating for 24 hours will not do you any harm as long as you drink enough to prevent dehydration. (If you are diabetic this is an exception and you should be under medical supervision.)

If you really miss having something in your mouth then you can overcome this by sucking sweets such as:

  • Mints
  • Gummy Bears
  • Wine gums
  • Fruit pastels
  • Jelly babies
  • Clear fruit sweets

You can also suck popsicles/ice pops and eat Jell-O/Jelly as long as they are not red or purple. So stick to lemon, lime or orange flavors. These things will not jeopardize your colonoscopy preparation.

How Do I Make Sure I Don't Get Dehydrated?

The colonoscopy preparation diet involves cutting out certain groups of foods.

It is not always obvious but we do get a lot of our fluids from certain foods especially fruits and vegetables.

When we are not eating these foods we need to drink more fluids to compensate or we risk becoming dehydrated.

It is important when following this diet to drink between 8 and 10 glasses of clear fluids every day.

After you have taken the laxative preparation you will have lots of diarrhea so it becomes even more important to drink plenty to replace the fluids you are losing. The laxative instructions will tell you how much you need to drink.

Colonoscopy Preparation - Getting Through the Day Before

Many people have said that the day before the colonoscopy is the worst day of the whole process and I found this myself. Colonoscopy preparation is not easy! Getting your bowel clean involves having a lot of diarrhea, usually some abdominal pain, very occasionally nausea or in some rare cases vomiting.

As we have said earlier make sure that you have a day where you do not have to go out or do anything.

Stay very close to the bathroom because the need to open your bowels can come on very suddenly. Some people actually set up camp in the bathroom with a chair or cushions and blankets to make it more comfortable.

Wear loose clothing that is easily removed as you may need to get undressed in a hurry!

Make sure you have some magazines, a good book or something nice to watch on screen to relieve the boredom and provide a distraction.

If you have abdominal pain then use a covered hot water bottle, heat pad or warm wheat bag on the area.

When you think that the diarrhea has stopped snuggle up with your favorite cushion in bed or on the couch and don't think about doing anything energetic!

How do I Cope With the Horrible Taste of the Colonoscopy Preparation Laxative?

Whichever brand you are given they all taste pretty disgusting so a bit of help is needed. They normally come in the form of a powder which is mixed with water. This makes a very salty tasting drink which can be hard to stomach for some people.

Tip #1

Make sure it is very cold when you drink it as the taste will be less noticeable. So, mix it up a little ahead and chill before drinking. Some people even put the prep in the freezer for a short while.

Tip #2

Mix with a flavored drink to disguise the taste. Some people like powdered lemonade, some add Gatorade or Lucozade. Most flavored drinks will do as long as they are clear and do not contain any bits. Avoid red colored fluids as they can affect the quality of the pictures.

Tip #3

Drink through a straw as you will not taste the fluid as much.

Tip #4

Clean your teeth after you have drunk the laxative to get rid of the taste from your mouth.

Tip #5

Some doctors will now prescribe a new generation of laxatives which come in tablet form and so do not taste as bad. These are not suitable for everybody as they can put more strain on the kidneys and so cannot be used if you have kidney problems or are elderly.

Tip #6

Some people find that the laxative drink makes them feel sick. If you are prone to sickness or if you want to be on the safe side ask your doctor to give you some anti-sickness medication to help with this problem.

How Can I Prevent Soreness?

It is inevitable that even if you have followed the colonoscopy preparation diet to the letter you will have some diarrhea as a result of the laxatives you have been prescribed.

This can cause soreness around the anus (butthole). To help prevent this happening use wet wipes. Make sure that they are flushable and some people find that using wipes that incorporate aloe vera are soothing.

Use some barrier cream around the area. This is the same kind of cream that is used for babies with diaper/nappy rash. A well known brand is Sudocrem or you can use zinc and castor oil cream or Vaseline.

What About Medications?

Iron and Vitamins

Seven days before the test you must stop taking any medications or vitamin supplements that contain iron because the black coloration it causes will interfere with visibility.

Painkillers and Anti-Diarrheal Medicines

Pain killers which contain codeine should be stopped four days before the test because they have a constipating effect. Also stop taking Loperamide (Lomotil).

Bulk Forming Laxatives

Bulk forming laxatives which contain husks to bulk out the stools like psyllium (Metamucil), methylcellulose (Citrucel, Celevac) and polycarbophil (FiberCon), isphaghula (Fybogel), sterculia (Normacol) should be stopped at least two days before the test and preferably earlier. Check with your doctor.

Stop eating bran and cereals containing bran at least 5 days before the test.

Blood Thinning Products

Your doctor should be made aware of any blood thinning medications that you are taking like Coumadin/Warfarin. One of the possible side effects during colonoscopy is a risk of bleeding, especially if a biopsy needs to be done or polyps removed. You may be asked by your doctor to stop your medication about 5 days before the test.  

The Contraceptive Pill

If you are taking contraceptive medication then the diarrhea caused by the colonoscopy preparation laxative will make it ineffective. You should continue taking your pills but either refrain from having sex or use other methods of contraception for at least 7 days after the diarrhea or vomiting stops.

What If I Have a Health Condition?

Make sure that your doctor knows about any pre-existing health conditions and any medications that you are taking.

This is especially important if you have kidney problems, a heart condition, diabetes or glaucoma.

Colonoscopy Preparation - It Will Be Ok!

If you have read this article you may be thinking that you do not want to go through all that! It does not sound fun but many many people have had this test and some are very grateful that their problem was caught early and dealt with.

It is definitely worth putting up with a bit of discomfort in order to know that your bowel is good condition or if you do find out that there is a problem so that it can be sorted out quickly and not cause you heartache in the future.

Follow the instructions given to you by your doctor and use the information in this article to help you to get through a difficult time.

Good colonoscopy preparation is vital because the last thing you want to happen is to be mid-test with the flexible camera in-situ and have the doctor say "sorry I can't carry on, visibility is poor". So make sure that you are clean and ready!

After the Colonoscopy

There is a lot of information about how to get your colonoscopy prep right but not so much about what to do afterwards.

Most people will bounce right back and have no problems although you should look out for any signs of bleeding and report them to your doctor immediately.

Your gut has had a massive clear out which many people may think is a good thing but unfortunately a lot of friendly bacteria can be cleared out at the same time. It is a very good idea to take a course of high quality probiotics following the test. Look for one with a high number of bacteria and a wide variety of strains.

Colonoscopy preparation is important but getting your bowel back on track afterwards is also important. Think of it like this, athletes warm up but they also cool down.

Diarrheanurse hopes that your colonoscopy preparation goes well and that you get good results from your test. If not then you will know what you are dealing with and have given yourself a chance to get the best treatment.

Well done for getting the test done. It is not the greatest fun in the world but it is an important way of checking on the condition of your bowel!

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Photo attributions:

Milk: Day Donaldson


Lentils: Justinc




Duck consomme: T.Tseng

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