In this study, we conducted a comprehensive analysis of four SNPs located within the NOS genes, NOS3 (including c.-786T>C (rs2070744), a 27 bp variable number tandem repeat (VNTR) in intron 4 (rs61722009), and c.894G>T, (p.Glu298Asp, rs1799983)) and NOS2 c.1823C>T (p.Ser608Leu, rs2297518), to investigate their potential association with sepsis onset and the development of severe complications and outcomes in patients with secondary peritonitis. Here, NOS2 is linked to Sepsis.