There are epidemiological data suggesting that excessive iodine intake may be associated with some types of thyroid cancer, but a direct causal relationship cannot be proven. Therefore, restriction of iodine intake in patients with thyroid cancer is not generally required at present. For the development of other thyroid diseases, although too much or too little iodine intake may be associated with it, there is no need to worry too much about iodine intake in healthy people with a balanced diet and reasonable consumption of iodised salt in daily life.