Preparation guide
Preparing for your colonoscopy
The doctor can only see the bowel clearly if it is completely clean, so a good preparation is the most important part of a colonoscopy. Follow this guide along with the clinic’s instructions; if anything is different, the clinic’s instructions come first.
If your written instructions from the clinic differ, follow those.
Step by step
17 days before
- Tell us if you take any blood thinner (aspirin, clopidogrel, warfarin or one of the newer blood thinners). This must be discussed several days ahead. Never stop it on your own.
- If you take iron tablets, stop them about a week before, if the doctor advises.
- If you have diabetes, ask the doctor how to adjust your tablets or insulin during the preparation.
- Collect your bowel-prep drink and written instructions from the clinic, and read them fully.
- Arrange for an adult to come with you and take you home, as you will usually have sedation.
23 days before
- Start a low-fibre diet (see the food lists below).
- Avoid seeds, whole grains, raw vegetables and fruit with skins or seeds.
- Drink plenty of water and other fluids through the day.
3The day before
- Have a light, low-fibre breakfast, then only clear liquids for the rest of the day, as advised.
- Avoid milk and any red or purple drinks, as they can look like blood in the bowel.
- In the evening, take the first part of the bowel-prep drink exactly as instructed.
- Stay near a toilet. You will have frequent loose motions; this is expected.
- Keep drinking clear liquids so you do not get dehydrated.
- If you have diabetes, check your sugar more often, as you are eating less.
4On the day
- Take the second part of the bowel-prep drink early in the morning, as instructed.
- Your stools should now be clear or light yellow liquid, without solid bits. If they are not, tell us before the test.
- Do not eat anything. Stop clear liquids at the time you were told.
- Take your morning BP medicines with a small sip of water, unless told otherwise.
- Come with an adult. After sedation, do not drive or ride a two-wheeler for the rest of the day.
Low-fibre foods that are fine (3 days before)
- Idli and plain dosa
- White rice
- Curd
- Well-cooked potato without the skin
- Clear soups
- Eggs
- Fish or chicken cooked without spices, if you eat non-veg
Foods to avoid (3 days before)
- Seeds, nuts and dry fruits
- Whole grains: brown rice, whole wheat, millets, oats
- Raw vegetables and salads
- Fruit with skins or seeds, such as guava and grapes
- Dal with husk and whole pulses
- Spicy and oily food
Clear liquids (the day before)
- Water
- Clear soup, strained
- Coconut water
- Light tea without milk
- Glucose water
- ORS
Medicines to ask about
- Blood thinners (aspirin, clopidogrel, warfarin, newer blood thinners): discuss these with us several days before, especially as polyps may be removed. Never stop them without advice.
- Iron tablets: usually stopped about a week before, if advised, as they darken the stools and make the bowel harder to clean.
- Diabetes tablets and insulin: these usually need adjusting while you are on clear liquids and on the test day, so ask the doctor.
- BP and heart medicines: usually taken as normal, with a small sip of water on the morning of the test.
- Constipation medicines, Ayurvedic and herbal medicines: include them in your medicine list and ask whether to continue.
What to bring
- Previous colonoscopy, endoscopy and scan reports.
- A written list of all your medicines.
- A photo ID and your appointment details.
- An adult to take you home after sedation.
- A change of comfortable, loose clothes.
Call the clinic if
- Severe abdominal pain or a hard, swollen tummy.
- You keep vomiting the bowel-prep drink and cannot finish it.
- Fainting, or feeling very dizzy or weak.
- No bowel movement a few hours after starting the prep.
- Black stools, a lot of bleeding from the back passage or vomiting blood after the test.
- Fever or chills after the test.
Questions patients ask
This page is general information reviewed by Dr. Tejaswini Tumma. It does not replace a consultation.