ST-899 is a novel platelet-activating factor (PAF) receptor antagonist. ST-899 can significantly reduce the mortality of mice with endotoxin (LPS)-induced shock. ST-899 can significantly inhibit the increase in serum tumor necrosis factor (TNF) levels induced by LPS, but has no effect on interleukin-6 (IL-6). The regulatory mechanism of ST-899 is to block the positive feedback loop between PAF and TNF, thereby reducing the inflammatory response. ST-899 can be used to study inflammatory diseases such as septic shock[1].