Even nowadays the therapy of severe, particularly of contrast remedy-induced hyperthyroidism is not without any problems. According to reports in literature the application of lithium salts seems to be an expedient from this dilemma. We controlled the effect of a short-term lithium therapy of 7 days in combination with methimazole in comparison to a group with methimazole monotherapy. The examination showed a good effectiveness and tolerability of the lithium methimazole therapy. While the decrease of the thyroxin concentration in the two groups was not different, in the group with combined therapy a more rapid per cent decrease of the triiodothyronine concentration appeared. In primarily strict selection of the therapy severe side-effects are not to be expected. According to the results yielded up to now the described form of therapy is an actual enrichment for selected forms of hyperthyreosis.