Malnutrition is very common in critically ill patients. According to the available data, a high percentage of patients (30-60%) suffers from some degree of malnutrition, and in 10-15% of patients malnutrition can be very severe. Patient's nutritional status usually worsens during hospitalization. In malnutrition, the functions of all organ systems change. Surgical treatment is a stress for the body, which leads to the predominant catabolic response with accelerated decomposition of the non-fat tissue, resulting in enhanced gluconeogenesis and negative nitrogen balance, which further compromise body's vital functions. Due to such physiological effects, malnutrition is followed by increased number of complications of the underlying disease, higher mortality rate, prolonged hospitalization and increased treatment costs. Malnutrition is common in clinical practice, so at the time of the admission, all patients should be checked for signs of malnutrition. After noticing the presence of the increased risk, it is necessary to make a plan for preoperative nutritional support, in order to prepare the patient optimally for the surgical procedure. It is also necessary to check the factors which might lead to further worsening of the nutritional status of the patient. With adequate screening and therapy, it is possible to improve patients' general condition and the outcome, as well as to reduce the percentage of complications, mortality rate and treatment costs.

Drugs, natural medicinal plant, animals and mineral materials, have a large and various application in official pharmacy and medicine. Carriers of multilateral pharmacological effects that those drugs shown, are chemically define as active components that are present in them. Methods of qualitative and quantitative analysis are used for the chemical investigation of components that drugs contain. Method of thin layer chromatography has been shown as very reliable. According to the chemical investigation of single drugs, it is possible to define a group of compound or single compound comparing them with standards. Relating to the usage of method of thin layer chromatography, it has been carried out investigation on presence of coumarins and flavonoids in domestic plant material that have wide everyday usage. Coumarins and flavonoids from the point of view of chemical belonging are phenol derivatives with important pharmacological effects. Applying method of thin layer chromatography, it is detected presence of coumarins and flavonoids substances in plant material that has been tested. Anethi graveolens fructus et folium (fruit and leaf of dill), Anethum graveolens L., Apiaceae, Avenae sativae fructus (fruit of oats), Avena sativa L., Poaceae and Asperulae odoratae herba (sweet woodruff), Asperula odorata L., Rubiaceae. Chromatograms are developed in systems cyclohexane-ethylacetat (13:7) and toluene-ether (1:1) saturated with 10% acetic acid, and visualisation by observing on UV lamp (254 and 366 nm), spraying with reagents KOH (10% ethanol solution) and diphenylboryloxyethylamine (1% methanol solution).