Ornithine alpha-ketoglutarate (OKG) is a salt formed of two molecules of ornithine and one molecule of alpha-ketoglutarate. OKG has been successfully used by the enteral and parenteral route in burn, traumatized, and surgical patients and in chronically malnourished subjects. According to the metabolic situation, OKG treatment decreases muscle protein catabolism and/or increases synthesis. In addition, OKG promotes wound healing. The mechanism of action of OKG is not fully understood, but the secretion of anabolic hormones (insulin, human growth hormone) and the synthesis of metabolites (glutamine, polyamines, arginine, ketoacids) may be involved.