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Colonoscopy patient information

A colonoscopy is an examination of the lower part of the gastrointestinal tract that allows the colon to be examined in full using a flexible optical instrument (endoscope). The examination will help your physician find out the causes of your complaints (such as lower abdominal pain, bleeding in the gut) and find visible changes in the colon (such as ulcers, inflammation, tumours). A colonoscopy is more accurate than an X-ray examination and allows tissue samples to be taken during the examination.

Preparation for the examination

Preparations for colonoscopy begin a week before the planned examination. Tell your physician before the examination if you are taking blood thinners (e.g. aspirin, including aspirin-like medications, warfarin, clopidogrel) and iron supplements so that your physician can plan your preparation for your examination. Also tell your physician about your allergies to medications and chronic illnesses.

The large intestine must be empty for the colonoscopy. Both a low-fibre diet and an oral solution are used to empty the bowel. Thorough preparation of the intestine is important to allow the informative observational examination to succeed.

Stop using iron supplements seven days before the examination.

Do the following at least four days before the examination:

  • High-fibre foods should be removed from the menu: fruits, berries (small-seeded berries, grapes, kiwis), vegetables (tomatoes, cabbage, cucumbers), mushrooms, nuts, seeds, whole grains (porridge, bread, muesli).
  • Suitable meals are, for example, cooked or steamed white fish, boiled chicken, dairy products, eggs, cheese, bread, margarine, potatoes, wheat flour biscuits and pasta products, jelly, broth without vegetables, ice cream.
  • You must buy medication for emptying the intestine for the examination from the pharmacy. This prescription will be given to you by the physician referring you for the examination.

It is recommended not to eat the day before colonoscopy. If you cannot go without eating, you can have a clear broth for breakfast. Jelly made from gelatine, juice lollies (iced juice), transparent gummy candies (e.g. gummy bears) are also allowed for lunch. Then, until the colonoscopy, do not eat anything, but drink enough (e.g. filter tea or coffee, water, mineral water, apple juice, lemonade, sports drinks (avoid red drinks). Sugar can be added to coffee or tea in the case of weakness or malaise. On the day before the examination, one to one and a half litres of water should be consumed (mineral water is also suitable).

The day before the study, bowel preparation begins, consisting of the complete emptying of the colon.

  • Prepare a bowel emptying solution (e.g. Fortrans, Eziclen, Cololyt, Moviprep, Picoprep) according to the instructions and whether the colonoscopy is performed in the morning or in the evening.
  • Start bowel emptying in the afternoon, e.g. at 14:00 (if the investigation is in the morning the next day), following the medication administration recommendations given to you by your physician. If the colonoscopy is scheduled for the next day at lunch time, such as 12:00, divide the bowel preparation solution in half, i.e. drink half the amount the night before and the other half in the early morning of the examination day (4-5 hours before the test).
  • The amount of liquid to drink is large (approx. four litres) and the peculiar salty/sweet taste of the bowel preparation solution may cause nausea. It helps if you drink the solution coolly or if you add, for example, lemon juice to improve the taste.
  • The use of medications before the examination is decided by the physician; essential medications prescribed to you, such as antihypertensives and heart drugs may be taken with water.
  • You must go to the toilet before the examination to empty the bowel completely.


For the examination, you will be asked to undress your lower body and put on disposable examination pants. During the examination, you lie on your back or on your left side with your knees bent against your chest. The colonoscope is inserted through the anus into the colon, and by dilating the colon with air, it is possible to find pathological changes. Due to the stretching of the bowel with air, you may experience mild abdominal pain and a feeling of fullness; usually the complaints will pass within a few hours. If necessary, tissue samples will be taken during the examination, which are sent to the laboratory for analysis. If a removable tumour or polyp is found during the examination, it is usually removed immediately during the same examination (a separate procedure for a self-paid study).

The examination lasts around 60 minutes.

If necessary, the examination is performed under anaesthesia. In this case, the anaesthetist will inject you with a sedative medication before the examination.

If your procedure will be performed under general anaesthesia (anaesthesia), please read the anaesthesia information leaflet in advance.

After the procedure

  • If the examination is performed under anaesthesia, you will be observed for at least 60 minutes after the investigation.
  • You should not drive a car on the same day, as the strong sedative given to you will significantly reduce your reaction speed. It would be good if you could bring a companion with you to the procedure who will take you back home after the investigation or, if you have come to the procedure alone, use a taxi to take you home.
  • We recommend that you do not plan tasks that require precision for the day of the examination.
  • The physician will inform you of the initial result of the colonoscopy after the examination.
  • The results of the analysis of the tissue sample will be completed in two to three weeks and you will be notified by the physician who referred you for the procedure.
  • After the examination, you may experience mild abdominal pain or bloating and you may be disturbed by more gas in the gut than usual. Complaints usually go away within a few hours. In the case of prolonged bloating, we recommend taking simethicone or charcoal tablets.
  • If you feel like it, you can eat and drink immediately after the examination, unless your physician has told you otherwise.
  • As the colon has been cleared on the day before the study, there may be no need to defecate the next day and there is no need to worry.


Colonoscopy is a safe method of examination in which complications are rare:

  • bleeding after sampling is usually minimal and does not require blood transfusions or surgery
  • perforation of the colon wall is very rare but may require surgery

If you develop a fever, severe abdominal pain or bleeding after the examination, contact our paid information line 1500 immediately or go to the emergency department of the nearest hospital.