The present invention addresses the problem of providing a composition which is usable as a novel anti-inflammatory agent. Inflammation such as stomatitis, oral mucositis, gingivitis and pneumonia can be ameliorated and/or prevented by using a composition which comprises olanexidine or a pharmacologically acceptable salt thereof. Preferably, the composition according to the present invention further comprises a poloxamer which is a block copolymer comprising a polyoxypropylene (POP) chain sandwiched between two polyoxyethylene (POE) chains.