Hypothyroidism has an insidious onset and a long duration, and many patients lack specific symptoms and signs, mainly manifesting as a decrease in metabolic rate and sympathetic excitability. Because thyroid hormone deficiency can affect all systems of the body, all systems are altered in hypothyroidism. The thyroid gland itself can be atrophied or enlarged. Some patients with primary hypothyroidism may develop pituitary enlargement if they are not treated in time, which can be recovered after treatment. 1, skin: dry skin, dermal mucopolysaccharide infiltration, body fluid storage. In severe cases, mucinous edema may occur. 2, digestive system: reduced metabolism, weight gain. Poor taste perception, atrophy of gastric mucosa, and decreased gastric acid secretion. One-third of the gastric lining cells are positive for antibodies, and pernicious anemia accounts for about 10%. Weak gastrointestinal motility, constipation. 3, cardiovascular system: decreased myocardial contractility, decreased cardiac output, and decreased activity tolerance. In severe cases, heart failure and pericardial effusion may occur. 4, respiratory system: hypoventilation, sleep apnea. 5.Hematological system: orthocytic and orthochromic anemia, decreased blood cell pressure. 6.Nervous system: indifferent expression, prolonged reflex time. 7, reproductive system: fertility, decreased libido. Women with menstrual disorders or heavy menstruation. 8, other endocrine system: hypothyroidism – primary hypoadrenalism, pituitary hypothyroidism. 9, other manifestations: various intermediate metabolism is low, enzyme clearance is reduced, cholesterol, triglyceride, low-density lipoprotein, muscle enzymes and other concentrations are increased. If combined with diabetes mellitus, the diabetes mellitus is relatively reduced, and the dosage of insulin and oral hypoglycemic drugs is reduced. If you find that you have developed some of the above symptoms, you should be alert. Be sure to observe your symptoms, and if there are suspected symptoms, you must seek medical attention earlier and get a diagnosis as soon as possible. This will enable you to get effective treatment early.