Iodine is an essential element for human health. Too much or too little iodine will be harmful to human health. The disadvantages of eating too much iodine-containing food are: 1, iodine excess has been highly valued by the international thyroid and endemic diseases in recent years. In 200 1 year, the international authoritative academic organization first put forward the definition of iodine excess (urinary iodine is greater than 300 μ g /L), and agreed that iodine excess can lead to a significant increase in the incidence of hypothyroidism, autoimmune thyroid diseases and papillary thyroid cancer. 2. Excessive consumption of iodine will cause adverse reactions such as iodine goiter, and even cause iodine-induced hyperthyroidism. Eating food with high iodine content will promote oil secretion. 4. It has a certain influence on the production of male sperm, which easily leads to male infertility. 5. Hyperthyroidism patients eat food with high iodine content, which is easy to promote thyroid tissue sclerosis, and the swollen lump is difficult to eliminate, making it difficult for patients to recover.