Arginine is considered a nutrient that enhances the immune response. Studies have shown arginine-supplemented immune formulas in helping decrease protein catabolism, improve nitrogen balance, enhance wound healing and wound strength resulted in less infection and shorter hospitalization days. Arginine has also been shown to support the immune system by enhancing lymphocyte proliferation and phagocytosis. Arginine may provide some benefits. However, recent meta-analysis conducted in a subgroup of critically ill patients by Heyland and colleagues revealed that arginine may be harmful to some group especially septic patients by stimulating nitric oxide (NO) production.