Disclosed is a compound which has an excellent S1P1 agonistic activity and isparticularly useful as an active ingredient for a prophylactic and/ortherapeutic agent fordiseases induced by undesirable lymphocyte infiltration or diseases induced byabnormalproliferation or accumulation of cells. Specifically disclosed are a 2H-chromene compoundand a derivative thereof, each of which has an S1P1 agonistic activity and canbe usedparticularly for the prevention and/or treatment of diseases induced byundesirablelymphocyte infiltration or diseases induced by abnormal proliferation oraccumulation ofcells.(see formula I)
