I. Etiology Environmental iodine deficiency is the main factor causing goiter simplex. In addition, certain foods and drugs can cause disorders in a certain part of the thyroxine synthesis and secretion process. 1. Deficiency of thyroxine raw material (iodine); 2. Increased need for thyroxine; 3. Disorders of thyroxine synthesis and secretion. Symptoms 1. thickening of the neck (enlargement of the thyroid gland to varying degrees); 2. symptoms caused by pressure on the surrounding organs, such as choking sensation in swallowing, breathlessness, and dryness in the throat; 3. can be followed by hyperthyroidism and malignant changes. Examination: Ultrasound, radionuclide imaging, nail function, etc. Treatment 1. For physiological goiter, it is advisable to eat more iodine-rich foods such as seaweed and nori. 2. For diffuse simple goiter under 20 years old, a small amount of goitre can be given. Major thyroidectomy should be considered in the following cases: clinical symptoms caused by compression of the trachea, esophagus or laryngeal nerve; post-thoracic goiter; giant goiter affecting life and work; nodular goiter with secondary hyperfunction; nodular goiter with suspected malignant change.