The present invention relates to a method for the treatment of urticaria which comprises administering to a patient in need thereof an effective amount of a compound which is 4-[(4-chlorophenyl)methyl]-2-({(2R)-1-[4-(4-{[3-(hexahydro-1H-azepin-1-yl)propyl]oxy}phenyl)butyl]-2-pyrrolidinyl}methyl)-1(2H)-phthalazinone,or a pharmaceutically acceptable salt thereof.