In clinic, there are hyperthyroidism, hypothyroidism and Hashimoto's thyroiditis. After drug treatment for hyperthyroidism, hypothyroidism may occur due to excessive drugs. How should hyperthyroidism become hypothyroidism? There are the following aspects: First, stop using anti hyperthyroidism drugs. Because excessive use of anti hyperthyroidism drugs may lead to hypothyroidism. Second, for hyperthyroidism to hypothyroidism, if hypothyroidism is serious, it should be considered to stop using anti hyperthyroidism drugs and change to anti hypothyroidism drugs. The anti hypothyroidism drug is mainly eugal. Third, more attention should be paid to diet when hyperthyroidism becomes hypothyroidism. Hyperthyroidism was originally a requirement of low iodine diet, while hypothyroidism may be due to iodine rich diet. Therefore, the things that could not be eaten before may be eaten again for hypothyroidism patients, which is a change that needs attention. In addition, pay more attention to rest, avoid fatigue, do not smoke and drink, and excessive entertainment.