OBJECTIVE:To study the dynamic changes and the role of serum cytokines in the systemic inflammatory response syndrome (SIRS)/and multiple organ dysfunction syndrome(MODS) caused by central nervous system (CNS) diseases and the relationships with the severity of SIRS/MODS. METHODS: Twenty six children with CNS diseases admitted to the PICU were assigned into the SIRS group (n=16) and non SIRS group (n=11). The levels of TNF α,IL 1β and IL 6 were determined using the immulite chemiluminescent immunometric analyzer for the two groups on day 1, 3 and 5. RESULTS: The levels TNF α,IL 1β and IL 6 in the SIRS group were remarkably higher than those in the non SIRS group on day 1, 3 and 5 (P< 0.05 ). In the SIRS group, the levels of TNF α,IL 1β and IL 6 in the MODS cases and death cases were significantly higher than those in the non MODS cases and non death cases on day 1, 3 and 5 (P< 0.01 ). Moreover, these indexes of the death patients remained high continuously. CONCLUSIONS:TNF α, IL 1β and IL 6 may be valuable in assessing the degree of severity and the prognosis of SIRS/MODS caused by CNS diseases. They are helpful in making effective treatments and preventive measures for SIRS/MODS caused by CNS diseases.