[Hyperthyroidism during treatment with kelp tablets].

A 50-year-old healthy woman started daily treatment with six iodine-containing kelp tablets (Kelpasan), containing 200 mg of kelp each, to lose weight; she took no other medication. Within two months she developed clinical and laboratory evidence of hyperthyroidism, which resolved spontaneously following discontinuation of the tablets. A causal relationship between the intake of the kelp preparation and the thyrotoxic episode could not be established beyond all possible doubt, but the clinical picture and clear temporal relationship strongly pointed in this direction.