We present the case of a 71 year old Swiss woman with a symptomatic rheumatic arthritis whose rheumatologist started a therapy with methotrexate. While the symptoms disappeared completely, the woman died about two months later suddenly. By then she got a cumulative dose of 160 mg. The forensic post-mortem examination showed a fibrosing alveolitis. If respiratory symptoms appear under methotrexat regimen therapy, immediate stopping the medication could be life-saving. In accordance to the chest x-ray a cortisone therapy can be established.