NO hyperproduction, the main vasoplegic mediator in experimental sepsis, will be described as one of its most likely determinant factors implicated in pneumonia type L, through the probable overexpression and dysregulation of NO‐generating enzymes like inducible NO synthase (iNOS) and indoleamine‐2,3‐dioxygenase‐1 (IDO). The gene discussed is NOS2; the disease is Sepsis.