The invention relates to pharmaceutical composition and the use of melatonin, either alone or in combination with at least one compound selected from the group consisting of L-arginine, a physiologically acceptable salt thereof, one or more other physiologically acceptable compounds associated with the synthesis of nitric oxide and mixtures thereof, for the manufacture of a medicament for the therapeutic treatment, prophylactic treatment and/or prevention of postoperative infectious and/or non-infections complications may be pneumonia, wound infection (wound dehiscence), intra-abdominal abscess, and urinary tract infections (UTI) or wherein the non-infectious complication may be anastomotic leak, or ischemia/reperfusion.
