A pharmaceutical composition comprising (a) a phosphodiesterase (PDE)-IV inhibitor or a pharmacologically acceptable salt thereof and (b) vitamin D or a vitamin D derivative or a pharmacologically acceptable salt thereof; a therapeutic and/or prophylactic agent for psoriasis comprising (a) a PDE-IV inhibitor or a pharmacologically acceptable salt thereof and (b) vitamin D or a vitamin D derivative or a pharmacologically acceptable salt thereof as active ingredients; a kit comprising (a) a first component comprising a PDE-IV inhibitor or a pharmacologically acceptable salt thereof and (b) a second component comprising vitamin D or a vitamin D derivative or a pharmacologically acceptable salt thereof; and others.
