Diffuse alveolar hemorrhage (DAH) is a rare & catastrophic complication of methimazole therapy. The author reports a 44-year old female with a history of hyperthyroidism & poor compliance to methimazole therapy, presented to the emergency department with complaints of massive hemoptysis & respiratory failure. Further investigation lead to the diagnosis of thyroid storm & she was started on methimazole, steroids & beta blockers. Despite appropriate treatment, the patient’s condition worsened. Further workup revealed that the patient had DAH. After ruling out other etiologies, methimazole induced DAH was postulated & the patient was switched to propylthiouracil & steroids. Repeat bronchoscopy did not reveal any additional signs of DAH & the patient made a good recovery.