Colonoscopy is an examination allowing us to look at the inner lining of the large intestine and the final part of the small intestine (terminal ileum).

Before colonoscopy

To perform the exam, the bowel must be cleansed a few days ahead, with special diet and laxatives. Proper cleansing is necessary, otherwise the exam will not be reliable and often it will not even be possible.

For this reason, patients must follow the instructions to the letter, to get good results. The type of preparation may be modified depending on the patient, their age, co-existing conditions and bowel habits.

If patients are on medications, they must inform the doctor, so it can be decided if some of the medications need to be discontinued or not.

Note that to remove any polyps that may be detected during the exam, blood coagulation medication may need to be interrupted or replaced, always after consulting the gastroenterologist as well as the treating physician who has prescribed the medication.

The doctor will ask if you have ever had an allergic reaction to any of the examination medications. Patients should come to the appointment together with a friend or relative, as they are not allowed to drive after the exam.


The endoscope is a long, very flexible tube, a few millimeters in diameter, which passes through the patients’ anus to inspect the large intestine. A light-emitting camera is affixed on its end. The recorded image is transmitted to a special high-resolution screen, where the gastroenterologist looks at the interior of the intestine.

At the beginning of the exam

Patients lie on the examination table on their left side. A special device monitoring the pulse rate and blood oxygen saturation during the exam is placed on their finger. A vein catheter is inserted, to administer the anesthesia.

Patients undergo sedation by an anesthesiologist, i.e. intravenous administration of propofol, and in a few seconds they are asleep.

During the exam

The inner lining of the large intestine is inspected during the exam. If deemed necessary, sample tissue (biopsies) is obtained from the organ linings using a special forceps that passes through the endoscope. Using magnification endoscopes, microscopic lesions that are not visible with conventional endoscopes can be detected, even without the need for biopsies.

The exam usually lasts about 10-20 minutes. During the colonoscopy, polyps may be detected, i.e. precancerous lesions on the intestine lining, which may be removed, always with the patients’ consent.

After the exam

Patients come around a few seconds after the exam. They remain in bed for some time, before they get up and discuss the exam results with the doctor.

After the exam and for the rest of the day, patients are not allowed to drive or operate any machinery, as their reflexes may be slower due to the administered anesthetic.


Why do I need a colonoscopy?

A colonoscopy is the best preventive examination for early detection and diagnosis of dangerous diseases, such as polyps and colon cancer, which are fully treatable if detected early.

Is it a painful procedure?

Since propofol is administered by an anesthesiologist, you do not feel anything during the exam. Moreover, because the examination is performed with administration of carbon dioxide instead of oxygen, there is almost no bloating after the exam.

How do I prepare for the colonoscopy?

The doctor will provide detailed instructions a few days prior to the exam.  You will need to abstain from some foods and buy laxatives from a pharmacy. You will follow a special diet for 2-3 days before the exam and you will also need to take a special laxative to cleanse the colon. The key to a good exam is to completely cleanse the large bowel.