AbstractThe effect on thyroid function was investigated in 22 patients undergoing arteriography with a new low osmolality contrast medium—sodium and meglumine ioxaglate (Hexabrix). Plasma thyroxine (T4), thyroxine resin uptake (TRU) and free thyroxine index (FTI) were measured before and at varying intervals up to 56 days after the arteriogram. Despite the large doses of Hexabrix used (up to 89.6 g of iodine), these tests of thyroid function did not reveal any significant change from pre-angiographic levels. It is concluded that Hexabrix as used for arteriography does not affect thyroid function.