The present invention provides agents for inhibiting production of interleuk in- 8 and for inhibiting granulocytes activation as well as novel method for curing inflammatory diseases. The agents for inhibiting production of interleukin-8, and for inhibiting granulocytes activation and for curing inflammatory diseases, which contain as an active ingredient, a carbostyril derivative represented by general formula (I) (wherein R is a halogen atom; the substitution site of a side-chain of formula (A) is 3- or 4-position in the carbostyril skeleton; and the carbon-carbon bond between 3- and 4- positions in the carbostyril skeleton is a single bond or a double bond) or pharmaceutically acceptable salt thereof.
