Hashimoto’s thyroiditis does not necessarily progress to hyperthyroidism or hypothyroidism, but has the potential to do so, and may progress to hyperthyroidism or hypothyroidism under certain circumstances, usually manifesting as hypothyroidism. Hashimoto’s thyroiditis is mainly due to an abnormal immune system that causes the thyroid tissue to attack itself, causing self-destruction of the thyroid tissue and impaired secretion, which manifests as hypothyroidism. At the same time, due to the antibody attack on the thyroid gland may cause impaired thyroid follicular function, causing impaired thyroxine synthesis, which may also manifest as hypothyroidism. Hyperthyroidism may be caused by overgrowth of the thyroid gland when there is insufficient destruction of the thyroid gland itself and when healthy thyroid tissue is compensating. It is recommended that patients combine their symptoms for further judgment and seek medical attention if hyperthyroidism or hypothyroidism occurs.