Preparing for your procedure

If you are having an endoscopy you will need to prepare your digestive tract. How you will prepare your digestive tract, will depend on the procedure you are having.

We need you to prepare your digestive tract so that the endoscopist can see the lining clearly, and check for anything suspicious or treat any abnormalities. If the bowel is not clean enough the procedure may need to be delayed and you will need to have another appointment.

We may need you to alter or stop your medication(s) before your procedure. Your GP should tell you if you need to change your medication(s) but to help us deliver the best care to you, please let the preassessment team know if you are on any medication(s).

It is very important to follow the instructions in your pre-procedure pack carefully to achieve a clean bowel. If you have not received your pre-procedure pack, or if you have any questions, please contact the Endoscopy department on 01752 438407.


If you are having a Gastroscopy, you will need to be nil by mouth six hours before your appointment time. Nil by mouth means that you will not be able to eat anything or take medication. You may still be able to have small sips of water. Your pre-procedure information and instructions will tell you if you can continue to have small sips of water and when to take your medicine before your appointment.


If you are having a Colonoscopy, you will be asked to prepare your lower digestive tract by following a low fibre diet and taking laxatives provided by the hospital.

You will start your low fibre diet 2 or 3 days before your procedure.

You will start taking your laxatives the day before your appointment either in the morning or in the evening. When you will start taking laxatives, will depend upon the time of your procedure.

Please stay close to a bathroom which you can access easily once you start taking the laxatives. Do not go into work or put yourself in a position which will make it difficult for you to immediately access a bathroom.

Preparing for a colonoscopy

Preparing for a colonoscopy

When we are preparing for a colonoscopy, we alter our diet.

We follow a low fibre diet, followed by a day of having soluble foods and a liquid only diet before taking our bowel prep.

We want to make it as easy as possible for our bodies to digest food so that we can clear our digestive tract; one of the ways we can do this is by avoiding foods which are high in fibre. Fibre is a type of carbohydrate that the body can't digest so it passes through the body undigested.

We need our lower digestive tract to be clear so the endoscopist can completely investigate the lining. By eating a low fibre diet, followed by a day of liquid and soluble foods, we make it easier for the body to digest what we eat and pass any remaining food in our system.

We take bowel prep before our appointment in order to completely clear our digestive systems.

We don’t want our low fibre diet to disrupt our day. To make our pre-procedure preparation as easy as possible, we have asked some of our patients how they prepare for their appointments.

Your personalised pre-procedure information will tell you when you need to move onto the different stages of bowel preparation.

By making small changes to our meals, we can make sure we are doing everything possible to have a successful procedure.

What is a low fibre diet?

What is a low fibre diet?

This is a diet which contains little or no fibre/roughage. The aim of this diet is to reduce the amount of undigested food that passes into the large bowel.

A low residue diet may help prevent blockages in your bowel by reducing foods that are poorly or partially digested.

Please be aware that very fatty foods, such as fried foods can also be difficult to digest and may cause discomfort if eaten in large quantities. For this reason we suggest that you avoid very fatty foods.

Foods to eat, and foods to avoid on a low fibre diet


 Foods allowed

 Foods to avoid

Breads and cereals

  • Any white bread, cakes, scones, pitta, chapattis, naan, ect.
  • Breakfast cereals made from rice or corn e.g. cornflakes, rice krispies, Frosties
  • Rich tea biscuits, shortcake, custard creams, wafers, cream crackers, water biscuits.
  • Potatoes without skins, instant mash, potato waffles, chips without skin
  • White rice, pasta macaroni, noodles.
  • Tinned spaghetti
  • Any wholemeal/brown/granary/fibre-enriched bread, cakes, malt loaf, scones, pitta, chapattis, tortilla wraps, ect.
  • Whole-wheat/oat-based cereals e.g. all bran, Weetabix, muesli, porridge.
  • Breakfast cereals containing fruit or nuts.
  • Digestives, oatcakes, or biscuits containing oats, flap jacks, wholemeal or wholegrain crackers, crackers with seeds, Ryvita.
  • Potato skins
  • Brown rice, pasta, macaroni, noodles.

Vegetables, fruit, pulses, beans and legumes

  • Sieved tomato sauces (no skin or seeds), tomato puree
  • Well cooked vegetables with no skin, seeds or stalks e.g. boiled swede, turnip or carrot, skinned mashed or creamed potatoes, softly cooked florets of cauliflower or broccoli.
  • Fruit juice without pith or bits.
  • Smoothies which are pureed.
  • Raw vegetables or salads
  • Sweetcorn and peas
  • Celery
  • Potato skins
  • Dried fruit
  • Citrus fruit and berries
  • Fruit juice with pith or bits
  • Smoothies with bits or lumps.
  • Fruit/nut scones, fruit cakes, coconut cake, carrot cake, other cakes containing fruit or nuts.
  • No pulses, beans or legumes like lentils, black beans, kidney beans, chickpeas, and hummus.

Fats, meat, fish, dairy and alternatives

  • Chicken, turkey, sausages, bacon
  • Meat pies (avoid tough or fatty meat).
  • All fresh, tinned, smoked fish and fish in white breadcrumbs/batter.
  • Eggs
  • Soya, Quorn, and tofu
  • Almond milk, coconut milk, hemp milk, dairy-free plain soy yoghurt.
  • All milk, butter, cheese, smooth yoghurts and ice-creams.
  • Fat is ok in moderation.
  • All red meats
  • Meat casseroles, pies, pasties containing vegetables, sausages with onions.
  • Fish in wholemeal breadcrumbs.
  • Yoghurts or ice-cream with pieces of fruit.

Desserts and sugary foods

  • Jelly type jams, marmalade without peel or lemon curd.
  • Chocolate
  • Boiled sweets.
  • Custard
  • Jelly
  • Smooth sorbet
  • Mousse
  • Pancakes made with white flour
  • Jam or marmalade containing fruit bits, seeds or peel.
  • Peanut butter
  • Cake, scones, or chocolate containing fruits or vegetables.
  • Sorbets with bits of fruit.
  • Red jelly


  • Tea
  • coffee
  • squash
  • sports drinks
  • fizzy drinks
  • milkshakes
  • water
  • milkshake syrups with real fruit and seeds.
  • Fizzy drinks or squash with red or purple colouring.


  • Clear or creamed soups e.g. tomato or chicken.
  • Packet soups
  • Soups containing chunky vegetables, lentils, or beans.


  • Tomato sauce, brown sauce, Worcester sauce, smooth mustard, vinegar, salad cream and mayonnaise.
  • Salt and pepper.
  • Marmite.
  • Gravy, white sauce, cheese sauce
  • Sauces which contain bits of fruit, vegetables, or seeds.
  • Pickles.
  • Herbs and spices.
  • All seeds.


  • Medicines you normally take
  • Medicines you have been told to stop by your GP and the endoscopy department.
  • Multi vitamins
  • Protein powders
  • Iron tablets

Low fibre diet day

Low fibre diet

Today we can still eat a lot of different foods, but we’ll need to start our low fibre diet and start having smaller meals.

It is important to drink plenty of fluids. Try to drink 2 litres (about 8 to 10 glasses) in a day.

We need to remove raw or cooked fruits and vegetables which are sliced or whole, very fatty foods and foods like brown bread, rice or pasta from our diets; although this may sound restrictive, this still leaves us with a lot of options to choose from.

We often don’t need to change our diets too much, just make little changes.

For example, if we are making a sauce for a curry or pasta, we just need to make sure it is smooth or pureed.  

If we are eating a sandwich or a pizza, we make sure we have white bread and remove any whole or sliced vegetables or fruits.

We can switch out high fibre foods like oats or Weetabix for breakfast cereals made from rice or corn.

If we want to have something like orange juice, make sure we are choosing smooth juice rather than orange juice with pulp. You can drink smoothies provided they are completely blended without bits or fruit or seeds.

Although we cannot have legumes like baked beans, we can have tinned foods like spaghetti hoops or creamed soups.

If you are struggling with the diet, we have made a list of foods which you can eat on a low fibre diet and foods you need to avoid. You can find this list above.

Liquid and soluble diet day

Liquid and soluble diet

Today will be more of a change from our usual routine. We want to stop putting any more food into our digestive systems.

Try to drink 2 litres (about 8 to 10 glasses) in total throughout the day (not including the bowel preparation solution).

You can drink tea or coffee with a small splash of milk. Do not drink alcohol.

We can still have soluble foods like boiled sweets and jelly.

For savoury flavours we can have vegetable, chicken or beef broths, clear strained soups and clear stocks.

We can have drinks like squash, fizzy drinks, sports drinks, lemonade, apple juice.

It is important to keep drinking water and include sugar and salt in our diet today.

Bowel prep laxatives

Nil by mouth

About 24 hours before our procedure, we need to start taking bowel prep laxatives.

The solutions taste better if they are served chilled. If you are struggling to drink the solution, you may want to mix it with squash and drink through a straw.

You may want to mix the solutions in advance and keep them in the fridge. You need to use them within 24 hours of being prepared.

It is very important to drink all of the solution and continue to drink water. You should aim to drink one glass for every hour you are awake.

Going to the bathroom

Going to the bathroom

You need to stay near a toilet when you start taking the bowel preparation solution.

You can expect to poo frequently and have diarrhoea (watery poo). This starts within 3 hours of taking the first amount (dose) and continues until after your last dose.

We plan when you take the bowel preparation solution carefully. This means that the effects wear off before you are due to travel to the hospital.

Side effects of bowel preparation

Side effects of bowel preparation

It is common to have some bloating (when your tummy feels full and uncomfortable) or stomach cramps.

You can use a barrier cream (a cream to protect the skin from damage or infection), such as zinc and castor oil, on your bottom. This can prevent soreness during your frequent trips to the toilet.

Keep drinking clear fluids to stop yourself from getting dehydrated. As a guide, try to drink about 1 glass every hour. Signs that you are dehydrated include dizziness, headache and confusion.

Please report any allergic reactions, such as a rash, itchiness or redness, to the endoscopy unit or your GP.

Please call the endoscopy unit if:

  • You are sick (vomit) at any time after taking the bowel preparation solution.
  • You have any concerns about the bowel preparation solution.

Call 999 if you have a reaction that causes:

  • Swelling of the face, lips, tongue or throat.

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