Goiter is the enlargement of the thyroid gland. Nowadays the most common cause of goiter is lack of iodine intake. Other causes can be due to hypo- or hyperthyroidism (means under or overproduction of thyroid hormones). Goiter might be uninodular, multinodular, or diffuse. Goitre is treated according to the cause. If the thyroid gland is producing too much T3 and T4, radioactive iodine is given to the patient to shrink the gland. If goitre is caused by iodine deficiency, small doses of iodide are given. If the goitre is associated with an underactive thyroid, thyroid supplements are used as treatment (synthetic thyroid hormone levothyroxine) .In extreme cases, a partial or complete thyroidectomy is required.