<b>Introduction:</b> There are many natural approaches that may improve the nutritional status in malnourished patients. Increased consumption of natural food is a more physiological, attractive, and available form of nutritional therapy of patients than medical nutrition. However, in specific clinical situations, oral nutritional supplements (ONS) may constitute a good support of nutritional management in malnourished cancer patients. Selecting proper ONS and their appropriate use may reduce the risk and progression of malnutrition and significantly affect oncological patient's treatment as well as decrease the rate of postoperative complications. Oral nutritional supplements should be the first nutritional choice to prevent and correct nutritional disorders in oncological surgery patients, especially during the pandemic, with the connected inability to visit patients. Despite this, many specialists recommend improperly adjusted preparations, and they do not consider all ailments and diseases of the patient. If ONS are overused or used inappropriately, they can cause many clinical disorders. </br></br> <b>Aim:</b> This paper aimed to help explain and understand the general recommendations on the proper administration of ONS, their benefits, and difficulties connected with their use in clinical practice.
Keywords: cancer; clinical nutrition; malnutrition; oral nutritional supplements.