The aim of the research is to investigate the antiendotoxin effects of sinomenine, fangchinoline, stachydrine, chuanxionggzine, oxymartrine and evodiamine. Endothelial cells were challenged with 1 μg/mL LPS for 3 h and treated respectively with six alkaloids at three concentrations (1,5 and 10 μg/mL). The cells were incubated at 37 ℃ in a cell incubator for 21 h. The supernatants were collected and analyzed for the levels of IL-1α, NO and 6-keto-PGF_1α by ELISA kits. The results revealed that sinomenine, oxymartrine and evodiamin inhibited the production of IL-1α; sinomenine, stachydrine and chuanxionggzine inhibited the secretion of NO; fangchinoline down-regulated 6-keto-PGF_1α expression. All these changes were significant. Altogether, these data suggested that six alkaloids would exert beneficial therapeutic effects on inflammation, edema and coagulation via these cytokines.