The clinical effects of administration of flora (probiotics), supplied fibers (prebiotics), and their combination (synbiotics) with or without enteral nutrition have been reported in meta-analysis of randomized control for critically ill and postoperative patients. The rate of infectious complication is improved by the probiotics/synbiotics treatment in major trauma and patients after gastroenterological surgery, but not acute severe pancreatitis and IUC critically ill patients. The use of probiotics/synbiotics as potential strategy of nutritional therapy is valuable for maintenance of the gut environment and systemic immunity in patients with severe surgical stress. Future major concerns are selection of probiotic species and prebiotics with their combination, their dosage, and duration of treatment.