INTRODUCTION The strict ‘nil-by-mouth’ from midnight rule, before elective surgery was introduced to ensure an empty stomach at the time of anaesthesia. Over the last decade several shown that more liberal rules may be of considerable benefit to the patient. Delayed gastric emptying is caused by operative trauma and perioperative stress response. Level of that stress response is determined by preoperative morbidity and also experience of all medical staff included in treatment. Within all fields of treatment several new methods are developed in order to reduce surgical stress. It has been shown that patients with more severe perioperative stress have more incidences of postoperative complications. Undernourished patients have more postoperative, mainly septic complications, higher mortality and increased costs of treatment. Even a short fasting period change patient’s response to stress. Early postoperative feeding stimulates gastrointestinal motility, prevents mucosal damage and translocations of microorganisms and with that reduces morbidity. Oral feeding intolerance is the most frequent cause for discontinuing oral feeding. Paracetamol absorption test is one of the most valuable tests for gastric emptying evaluation and continuing oral feeding. AIM The aim of the present study was to investigate the possible effects of preoperative carbohydrate fluid administration on postoperative perioperative stress response and postoperative gastric emptying. METHODS Study is prospective, randomized, double blinded study. A total of 116 patients with cholelithiasis and colorectal carcinoma were included. They were randomized in the group 1 (with preoperative enteral feeding) and group 2 (with standard protocol “nothing by mouth” 12 to 16 hours prior to surgery). Stress response has been evaluated through changes in concentration of interleukins 6, 10 and tumor necrosis factor and non-specific parameters as C-reactive proteins and cortisol. For the evaluation of the gastric emptying and gastroduodenal motility paracetamol absorption test has been used. RESULTS After laparoscopic cholecystectomy in patients who did not received preoperative feeding rise in CRP concentration is significantly higher. Afternoon cortisol levels in both groups rise above morning levels. Cortisol levels after laparoscopic cholecystectomy in patients with preoperative feeding afternoon shows normal physiological decline whereas in fasted group cortisol concentration rise over morning levels. In patients with oral feeding IL-6 postoperative levels are significantly lower than in fasted group. (60,9 vs 144,1 pg/ml; p<0,01). Paracetamol concentration rises faster and higher in the group with feeding 60 minutes after administration. After colorectal resections paracetamol concentrations is higher at 60 minutes in group with feeding, while in fasted group maximal concentrations are achieved only after 120 minutes. CONCLUSIONS According to presented results it could be stated that preoperative oral feeding has some influence on stress response. With preoperative oral feeding in all patients, recovery of the normal gastric emptying is faster than in fasted patients.