Systemic inflammatory reactions are pivotal in many disorders and have important secondary influences in many more. Although inflammation is initially useful to limit infection, it can also be detrimental and cause organ failure. Modulation of systemic reactions is important to restrict mediator release and limit cell activation that could cause harmful consequences. Experiments in which different models and treatments were used show that melanocortins reduce host responses such as fever, shock, reperfusion injury and allograft rejection. Melanocortin-derived peptides could be an effective treatment to prevent organ failure caused by excessive production of pro-inflammatory mediators. The degree of the modulatory effect exerted by melanocortins should be sufficient to reduce severity of systemic inflammation without impairing the host defense mechanisms.