The synthesis and secretion of inflammatory cytokines in the monocytes of 68 cases of multiple system organ failure (MSOF) patients was investigated by the method of MTT stained in cytokines dependent defferential cell strain. The data showed that the serum levels of tumor necrosis factor, interleukine 1 and interleukine 6 were increased (Ｐ＜0.01) in the monocytes of MSOF patients. The synthesis and secretion of these inflammatory cytokines gradually increased in the monocytes after onset of MSOF. After 5 days of treatment with antibiotics and electrolytes intravenous infusion, the secretion of TNF, IL-1 and IL-6 were decreased respectively. These results suggested that the TNF, IL-1 and IL-6 are integrated into system inflammatory responese and caused the injury to the tissues and organs. The production levels of these cytokines can be regarded as the index of MSOF and its severity.