The invention provides methods and compositions for preventing or treating (e.g., slowing the progression of, arresting, and/or reversing) calciphylaxis in a subject in need thereof and, more particularly, the invention relates to methods of using menaquinone-7 (MK-7) and/or menaquinol-7 (MKH2-7) for preventing or treating calciphylaxis in a subject with one or more of the following: diabetes, chronic kidney disease, end stage renal failure, and COPD or a subject undergoing hemodialysis and/or receiving anticoagulant therapy and/or statin therapy.