Thyroid crises masquerade as many illnesses. Identification of these processes is difficult and requires a high index of suspicion. Clinical diagnosis is necessary in the ED, as no emergent confirmatory test exists. The treatment is unique and can be intimidating because of the severity of possible adverse effects. The replacement of thyroid hormone and inhibition of thyroid hormone production has not changed much in the past 2 decades. Choices of vasopressor agents and beta-blocking agents have broadened. However, a clear "correct" choice cannot be defined, as thyroid crises often coexist with other acute and chronic diagnoses. The emergency clinician should focus on treatment of the thyroid, supportive care, and identification of coexistent acute processes.