5,8,11-ETI is a nonselective inhibitor of lipoxygenases. It inhibits 12-LO in human platelets with an ID50 value of 24 μM.{66} 5,8,11-ETI also inhibits A23187 and L-cysteine induced LTC4 biosynthesis in mouse mastocytoma cells with an ID50 value of 5 μM.{650} At higher concentrations, 5,8,11-ETI also inhibits cyclooxygenases (ID50 = 340 μM).{66}