The thyroid gland is an important endocrine gland in the human body. The main role of the thyroid gland is to secrete thyroid hormones, which have the ability to promote the body’s metabolism, promote growth and development, and affect the development of the nervous system. When the size of the thyroid gland is reduced, hypothyroidism is most likely to occur. The main hazards of hypothyroidism are: i. Low metabolic symptoms, mainly manifested as fear of cold, fatigue and weakness, swelling of the face and eyelids, weight gain, memory loss and unresponsiveness. Second, hypothyroidism affects the contractility of the heart muscle, resulting in slowed heart rate and pericardial effusion, etc. Third, hypothyroidism affects lipid metabolism, causing hypercholesterolemia and aggravating the development of atherosclerosis. Fourth, in severe hypothyroidism, mucinous edema and coma can occur. V. Hypothyroidism in women can affect the neurological development of the fetus when pregnancy occurs.