<;P>;PROBLEM TO BE SOLVED: To prevent or treat bronchial asthma, allergic rhinitis and pollinosis, by inhibiting the expression or isolation of leucotriene. <;P>;SOLUTION: This leukotriene expression or isolation inhibitor is prepared by using propolis or its extract as an active ingredient. The preventing or treating agent of the bronchial asthma is prepared by using the propolis or its extract as an active ingredient. <;P>;COPYRIGHT: (C)2008,JPO&INPIT