Methotrexate (MTX) is an antifolic drug used in the treatment of immune-mediated and neoplastic diseases. Initiation or dosage changes in MTX therapy can cause mucositis and bone marrow suppression. Skin lesions due to acute MTX toxicity are rare, but they serve as a herald for later-onset pancytopenia. Therefore, identification of those cutaneous lesions might help to initiate rescue strategies at an early stage. Here we describe a case with mucocutaneous ulcerations and pancytopenia due to overdosed MTX.