This case involves a post-menopausal female patient who was prescribed the hormone supplement medroxyprogesterone to prevent overgrowth of her uterine lining. When the patient went to the pharmacy to pick up her medication, she was accidentally dispensed a high dosage of methotrexate, an immunosuppressive used to treat rheumatoid arthritis. This incorrect dosage led to various negative side effects, including frequent falling, weakness, nausea and diarrhea, and vomiting. The patient presented to the hospital with multiple medical findings consistent with methotrexate poisoning. Her renal function was severely impaired and she was transfused with packed red blood cells and platelets. This pharmacy error caused irreparable kidney damage to the patient and she subsequently required a kidney transplant.