Summary: Colonoscopy is one of the basic diagnostic and surgical procedures in gastrointestinal endoscopy. A key element of the quality, duration of the examination and patient comfort is the grade of colon preparation. According to the latest guidelines, a split-dose preparation is recommended as more effective than a same-day bowel preparation. There are a number of preparations available on the market, which allows to individualize the selection depending on the clinical history of the patient.