Colonoscopy Diet

Colonoscopy Diet

Importance of Preparation

Diet is an integral part of preparing for colonoscopy, regardless of whether it is the traditional or virtual optical exam.


A good preparation for colonoscopy is made up of three key elements:

  • possible adjustment of pharmacological therapies in progress and adoption of other prophylactic measures;
  • low-fiber diet;
  • use of drugs with a laxative effect.

These precautions are fundamental, as:


  • they allow you to clean the intestine well, an aspect that is essential for the success of the examination (see figure on the side);
  • cause less discomfort during colonoscopy;
  • reduce the risk of complications.

Important premises

  1. If the patient does not strictly follow the instructions given by the medical center on proper preparation for the colonoscopy, the procedure may need to be repeated. In fact, if the intestinal walls are not sufficiently free from fecal residues, the doctor may decide to stop the investigation and postpone the colonoscopy.
  2. In preparing for colonoscopy, some general MA rules can be defined:
    • each medical center to which one turns to tends to adopt its own protocol, which in the final analysis is always and in any case "sewn on" the patient should it be necessary to personalize some aspects, for example due to intolerances or allergies, diabetes, pregnancy, diseases inflammatory bowel disease, use of certain drugs such as coumadin or clopidogrel, opportunities for antibiotic prophylaxis, etc.
    • In light of these considerations, the reader must always and in any case rely on the instructions provided by the medical center, even when they conflict with the notions present in this article.

Diet for colonoscopy

Diet is an integral part of any colonoscopy preparation process. The ultimate goal of this intervention is to thoroughly cleanse the walls of the intestine from fecal residues, which could remain despite taking the purgative:



  • hiding small polyps or other formations
  • making it difficult to observe the mucous membrane of the bowel
  • increasing the inconvenience for the patient

Examples of diseases and conditions to report to the medical center to obtain a safe and personalized colonoscopy preparation protocol:

  • diabetes
  • glaucoma
  • diverticula
  • myocardial infarction within the past 6 months
  • other heart diseases (e.g. mitral prolapse, other valvulopathies, etc.)
  • presence of pacemakers or artificial heart valves
  • allergies of any kind
  • previous allergic reactions to certain drugs or anesthetics
  • use of antiplatelet and anticoagulant drugs

To obtain a correct intestinal cleansing it is always recommended to take a purgative by mouth. In this regard, there are differences between the protocols adopted by the various endoscopic centers, which in the final analysis are always and in any case adapted to the individual patient (if certain disorders or conditions are present, see table). It is therefore advisable to strictly follow the instructions received regarding the type of purgative to be used, the dosage and methods of intake.

La colonoscopy diet is important because some eating habits can favor a greater efficacy of the laxative. Let's see some general rules:


  • From 5/7 days before the exam:
    • suspend the intake of fruit and vegetables with seeds (such as grapes, kiwis, figs, strawberries, aubergines, tomatoes and the like);
    • stop taking food supplements containing iron (which tends to color the intestinal walls black and has a constipating effect);
    • PLEASE NOTE: most centers restrict all these constraints to just 3 days before the colonoscopy
  • From 2/3 days before the exam
    • drink at least two liters of non-carbonated water per day (some centers recommend reaching 3 liters of water per day);
    • avoid large meals;
    • eliminate from the diet
      • all foods rich in slag (fiber), such as vegetables, legumes, fruit and fruit juices with pulp, whole grains (pasta, bread, biscuits, fiber-rich breakfast cereals, etc.), fatty meats and cheeses, chocolate , alcoholic beverages
      • avoid foods rich in dyes (packaged foods with a particularly bright color)
      • avoid nuts and nuts in general, including foods that contain them (e.g. some cakes or sweets, peanut butter, muesli, etc.)
      • avoid soups or jams containing traces of peel or seeds (eg strawberry jam and tomato jam);
    • the diet must therefore be based mainly on animal foods: eggs, lean meat, fish and broth, low-fat cheeses, homogenized with small quantities of white bread. As a condiment, olive oil can be used in modest quantities. Yogurt is sometimes allowed, as long as it does not contain pieces of fruit; milk only if skimmed. Potatoes can also be eaten, as long as the peel is removed.
    • Remember that above all there is always the main rule of avoiding large meals; the colonoscopy diet provides for limiting the portions of food consumed in the 2/3 days prior to the examination.
    • Stop taking vegetable charcoal, often present in some preparations for the problems of meteorism, flatulence and swollen stomach, and other food supplements
  • 1/2 days before the exam
    • Fasting or semi-fasting is generally recommended (diet based only on liquid foods, chosen from those allowed (avoiding corrections with milk and dairy products): water, tea, barley coffee, chamomile, sweetened and unsweetened or sweetened with honey;
    • It is necessary to follow the protocol concerning the correct intake of the purgative (e.g. polyethylene glycol, bisacodyl, saline and osmotives → isocolan etc.)
  • Two hours before the exam
    • Completely stop drinking fluids.

PLEASE NOTE: in case of virtual colonoscopy many of the above rules apply, even if in general the diet is less restrictive. The risk, in this case, is that any fecal residues can be mistaken for polyps or other formations, increasing the risk of false positives.



If the subject suffers from chronic constipation, some studies overturn the rules just seen, suggesting a diet rich in fiber (in order to improve intestinal transit and allow a complete cleansing of the colon).



The above are just some general rules of the colonoscopy diet; we remind you that these indications vary slightly from one medical center to another. Therefore, in case of doubts, it is advisable to contact the medical center where the colonoscopy will be held.


Other articles on 'Colonoscopy Diet'

  1. Preparation for Colonoscopy
  2. Colonoscopy
  3. Prepare for Colonoscopy with Herbs
  4. Diet after colonoscopy
  5. Virtual Colonoscopy
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