The　frequency　of　methylisothiazolinone　(MIT)-related　health　concerns　regarding　allergic　contact　dermatitis　with　a　spongiotic　reaction　pattern　and　restrictive　lung　function　indicating　peripheral　airway　dysfunction　caused　by　the　use　of　humidifier　disinfectant　is　increasingly　rising.　There　is　a　limited　number　of　evidences　supporting　the　environmentally　acute　and　mass　exposure　to　MIT　resulting　in　acute　respiratory　distress　syndrome　(ARDS).　Here,　we　report　the　first　case　of　ARDS　and　alimentary　tract　hemorrhage　following　mass　ingestion　of　methylisothiazolinone.