Leukotrienes (LT), mediators on allergic asthma and inflammation, are formed from arachidonic acid by 5-lipoxygenase. An attempt was made to develop an orally effective anti-allergic drug. Caffeic acid was found to inhibit 5-lipoxygenase. We synthesized about 200 derivatives of caffeic acid. Among its derivatives, TMK-688, 1- (3- (5- (3-methoxy-4-ethoxycarbonyloxy) -1-oxo-2, 4-pentadienyl) aminoethyl) -4-benzhydryloxy-piperidine, was finally selected to be the most suitable drug. TMK-688 showed significant inhibition in various models of allergic reactions and non-allergic reaction, i.e., 1. Inhibition of IgE-mediated passive cutaneous anaphylaxis in rats. 2. Inhibition of direct passive Arthus reaction in rats. 3. Inhibition of anaphylactic bronchoconstriction in guinea-pig. 4. Inhibition of histamine-induced smooth muscle contraction in guinea-pigs trachea. 5. Inhibition of platelet activating factor-induced bronchoconstriction in guinea-pigs, etc.Above all results suggest that TMK-688 is a unique orally active anti-allergic drug.