What to Eat Before and After a Colonoscopy?

One of the most important things to keep in mind when undergoing a colonoscopy is the “dietary restrictions”. The details vary from hospital to hospital, but in general, there are rules about when you can eat and drink and what foods you can eat and drink before and after the examination.

Meals Before the Colonoscopy

Food the day before the colonoscopy

When undergoing a colonoscopy, you can have dinner the day before. However, please note that there are restrictions on the time and content of the meal.

Colonoscopy is usually done in the morning. Eating and drinking after a certain time are prohibited because food residue or a lot of stool in the stomach or intestines during the examination can interfere with the examination. In many hospitals, you will be instructed to finish your dinner between 5:00 pm and 9:00 pm. The time when you are allowed to eat depends on the hospital where you are having the examination, so be sure to follow the instructions given by the hospital. In the case of a colonoscopy, you may have to take a laxative the day before.

On the day before, you need to avoid high-fiber foods and oily dishes for breakfast, lunch, and dinner. Try to eat as much easily digestible food as possible in small amounts. Some hospitals offer special “test meals” that are easy to digest and do not turn into stools. Some hospitals may impose dietary restrictions a few days before the colonoscopy, so be sure to get a proper explanation beforehand and follow the instructions.

Food on the morning of the colonoscopy

On the day of the procedure, breakfast is generally not allowed (in the case of esophageal and gastric examinations, a small amount may be allowed depending on the time of the examination). However, in most cases, only drinks can be consumed until about two hours before the examination. At this time, dark-colored drinks and milk drinks are not allowed. It is best to drink water or tea. Depending on the hospital, you may be instructed to drink a few glasses of water a few hours before the examination.

Eating After Colonoscopy

When can you eat after the examination?

During a colonoscopy, sedatives or anesthesia may be used to ease the pain of the examination. Also, during colonoscopy, the movement of the colon is inhibited by injections. Even after the test is completed, you will not be allowed to eat until the effects of the anesthesia and drugs wear off. The instructions vary from hospital to hospital, but in most cases, you will be allowed to eat after one or two hours of the test.

Dietary restrictions after the test

After the effects of the medication have worn off, it is advisable to consume food and drinks conscientiously to prevent hypoglycemia and dehydration. Some hospitals allow patients to return to their usual diet, but in most cases, patients are instructed to avoid stimulants. Also, some hospitals advise patients to avoid living things, oily foods, and alcohol for a few days after the test. In any case, it is best not to judge for yourself, but to ask your doctor before deciding what to eat.

Dietary restrictions when polyps have been removed

During a colonoscopy, the mucous membranes and tissues of the digestive organs may be collected for further examination, and polyps and other lesions may be removed for treatment. It is best to avoid alcohol and irritants, as the digestive tract can be very rough after tissue sampling and lesion removal. In some cases, it may be necessary to eat a gastrointestinal-friendly diet for a few days to a week.

In some cases, you may need to eat a gastrointestinal-friendly diet for a few days to a week. If you have a large polyp removed, you may need to fast after the surgery to avoid the risk of bleeding. After the next day, depending on the results of the medical examination, you will start with a liquid diet and gradually return to a normal diet.

What You Can And Cannot Eat Before And After Colonoscopy

What you can eat

Foods that can be eaten are those that are considered to be easily digestible. Specifically, the following foods can be eaten:

  • The bread that does not contain cereals and is not covered with jam or butter (honey is okay).
  • White rice or porridge
  • Noodles such as udon and somen (hospitals seem to have different opinions about soba)
  • Eggs
  • Tofu, soy milk
  • Meat (including ham, bacon, sausage, etc.)
  • Fish (including fish paste)
  • Soups such as miso soup and consomm√© soup

Try to eat a combination of the above items, in moderate amounts, and as early in the day as possible.

The following beverages are considered to be good:

  • Water
  • Green tea, oolong tea, and other teas
  • Sports drinks
  • Carbonated drinks
  • Coffee (no milk, sugar allowed)

What not to eat

On the contrary, the foods that should not be eaten are those that are rich in fats, oils, and dietary fiber. They are hard to digest and increase the amount of stool, so they are considered to interfere with the test.

  • Vegetables
  • Fruits
  • Beans and sesame seeds
  • Konjac
  • Seaweed
  • Mushrooms
  • Stimulants (spices, condiments, etc.)
  • Dairy products
  • Rice cereals, brown rice, and germ bread, which are generally considered to be healthy, are also foods that should be avoided before the test.
  • In terms of beverages
  • Alcohol
  • Milk and other dairy drinks
  • 100% juice
  • and other beverages should be avoided.

The range of acceptable and unacceptable food items and the period they should be restricted vary from hospital to hospital. The restrictions may also vary depending on pre-existing conditions such as constipation or diabetes. Check the pre-test instructions and pamphlets carefully, and try to follow the doctor’s instructions.

Diet to Ease Preoperative Laxatives

Before a colonoscopy, a laxative is used to expel the contents of the intestines. Many people have a hard time with this laxative elimination. It is said that if you do not eat any solid food the day before, and only eat very soft food such as jelly and drink, the amount of laxative can be reduced and the evacuation can be completed somewhat easily.

Eating Right According to the Doctor’s Instructions is Important

Before undergoing a colonoscopy, various dietary restrictions are imposed. Not only are there restrictions on foods such as “high in fat and oil” and “high in fiber,” but there are also restrictions on the time of eating. Therefore, it may seem a little troublesome. However, adhering to the dietary restrictions is necessary for a smooth examination and a more accurate diagnosis.

After the test, there are also restrictions on the timing and ingredients of the food you eat. Even if you have gone through all the trouble to have your health checked, it would not be good if your health is harmed by the food you eat after the test. It is important to follow the instructions given by the doctor or nurse before and after the test. If you have any questions, even if they are trivial, be sure to ask for confirmation beforehand.


As for what to eat before a colonoscopy, there is almost no problem with stomach exams as long as you keep the time you eat. However, when it comes to colonoscopy, the intestines need to be completely clean before the examination can be performed. At our clinic, we meet with the patient before the examination to give laxatives and explain the diet, but some people say that it is a bit troublesome.

Some people may say, “It’s a bit of a hassle.” The patient indeed needs time to prepare and deal with things beforehand, so it may seem troublesome. However, in most cases, simply paying attention to the meal the day before is enough to deal with the situation, and I tell them that drinks other than water are fine as long as the bottom of the drink can be seen, even if it is colored such as tea. Some facilities provide the kind of food described in the article, so why not take advantage of it?

However, if you are constipated, you may not be able to clear your bowels only by eating the previous day’s meal, so it is recommended that you receive advice from your doctor at the facility where you will undergo the test.