Aim:To study the anti-endotoxic effect of o-aminobenzoic acid(OABA)isolatedfrom Banlangen(BLG).Methods:OABA was extracted and isolated from BLG anddiluted into 0.5% solution.The concentration of endotoxin(ET)pretreated withOABA was quantitatively detected using Limulus test.The inhibition of ET-induced fever by OABA was measured in rabbits.The rates of lipopolysaccha-rides(LPS)-induced death in mice pretreated with or without OABA were thencompared.The influence of OABA on the release of TNF-α and NO from mac-rophages induced by LPS was examined in mice.Results:After pretreatment withOABA,84.4% of ET was destroyed.The ET-induced fever in rabbits decreasedsignificantly and the rate of LPS-induced death in mice dropped from 70% to 20%.The release of TNF-α and NO induced by LPS in mice was inhibited dose-depen-dently when the concentration of OABA was between 0.125% and 0.5%.Conclusion:OABA isolated from BLG has an anti-endotoxic effect. Aim:To study the anti-endotoxic effect of o-aminobenzoic acid(OABA)isolated from Banlangen(BLG).Methods:OABA was extracted and isolated from BLG anddiluted into 0.5% solution.The concentration of endotoxin(ET)pretreated withOABA was quantitatively detected Using Limulus test.The inhibition of ET-induced fever by OABA was measured in rabbits.The rates of lipopolysaccha-rides(LPS)-induced death in mice pretreated with or OABA were thencompared.The influence of OABA on the release of TNF- α and NO from mac-rophages induced by LPS was examined in mice.Results:After pretreatment withOABA,84.4% of ET was destroyed.The ET-induced fever in rabbits declinedsignificantly and the rate of LPS-induced death in mice dropped from 70% To 20%.The release of TNF-α and NO induced by LPS in mice was inhibited dose-depen-dently when the concentration of OABA was between 0.125% and 0.5%.Conclusion:OABA isolated from BLG has an anti-endotoxic effect.