ABSTRACT Four patients with Jodbasedow (iodine-induced hyperthyroidism), who experienced a spontaneous remission of thyrotoxicosis within a few months without specific antithyroid treatment are described. All the patients lived in a non-endemic area and had a nodular goitre. All of them gave a story of administration of iodine-rich compounds such as contrast medium for cholecystography or iodine-containing exceptorants, just before the appearance of thyrotoxic symptoms. The rapid improvement of hyperthyroid symptoms after avoiding excessive iodine administration strengthens the causal relationship in Jodbasedow. Though a definitive statement on the best treatment of this disease must await further studies. the present report provides some reason for believing that Jodbasedow is a benign type of thyrotoxicosis, which responds well to conservative treatment without ablation by surgery or radioiodine. Furthermore, the present findings emphasize previous warnings against the administration of unphysiologically large amount of iodine to euthyroid goitre patients because of the risk of precipitating thyroid dysfunction.