We reviewed systematically and aggregated statistically the results of prospective randomized clinical trials to examine the relations among the nutrition interventions, complications, and mortality rates. We conducted a search for prospective randomized clinical trials comparing the effects of enteral and parenteral nutrition in adults. Two different people abstracted data for the method and outcomes separately. We used fixed-effects meta-analysis technique to combine the relative risks of the outcomes of infection, nutrition support complications, other complications, and mortality.