Hyperthyroidism is a disease due to an over effect of the thyroid hormone. The essential cause is unknown; the patients have an elevated metabolism that gives many symptoms. The majority has Graves´ disease with goitre and ophthalmopathy. The affliction prevails among young adults, women forming the vast majority. The three pillars of treatment are: drugs inhibiting the thyroid function, radiation and surgery. The latter used to include the risk of paralysis of the vocal cords and hypoparathyroidism but is at present a safe intervention.