The purpose is to provide a compound which can overcomes the disadvantages of conventional steroid drugs and NSAID. It is found that specific epoxy monohydroxy forms of eicosapentaenoic acid, docosahexaenoic acid and docosapentaenoic acid which are independently represented by formulae [chemical formula 1], [chemical formula 5] and the like have an inhibitory activity on neutrophils. This compound can inhibit the invasion of neutrophils into tissues and the activation of neutrophils which are observed in acute inflammations.