The serum concentration of IL‐18 was (776.99; 653.48–952.39 pg/mL) in hepatitis C, (911; 775.55–1130.03 pg/mL) in fatty liver, (1048.88; 730.04–1185.10 pg/mL) in liver cancer, and (949.12; 723.70–1160.28 pg/mL) in hepatitis B. Moreover, IL‐18 serum levels were significantly higher in patients than the healthy controls (483.09; 402.52–599.70/mL) (p < 0.0001). This evidence concerns the gene IL18 and hepatitis B virus infection.