The thyroid gland is an endocrine organ located in the neck, and hyperthyroidism is a disease that is caused by thyrotoxicosis due to excessive production of thyroid hormones by the thyroid gland itself. The thyroid gland is the largest endocrine gland in the body. Thyroid hormones are synthesized by thyroid follicular epithelial cells and stored in the follicular cavity in colloidal form. Thyroid hormones widely regulate a variety of functional activities of the body, including growth and development (promoting growth and development), metabolism (enhancing energy metabolism, regulating material metabolism, and influencing organ system function). It is because the thyroid hormones synthesized and secreted by the thyroid gland have these functional effects that when thyroid hormones are secreted in excess, hyperthyroidism may result. The causes of hyperthyroidism include diffuse toxic goiter (Graves’ disease), nodular toxic goiter, and autonomic hyperfunctioning adenoma of the thyroid gland. The main symptoms include hyperphagia, weight loss, fear of heat, excessive sweating, palpitations, agitation, irritability, insomnia, fatigue, increased stool frequency or diarrhea, protruding eyes, enlarged thyroid gland, and scanty menstruation in women. There are also some special types of hyperthyroidism including: thyroid crisis, thyrotoxic heart disease, hyperthyroidism during pregnancy, indifferent hyperthyroidism, etc. There will be some special symptoms manifested. And the severity of hyperthyroidism signs and symptoms is related to factors such as the length of medical history, the degree of hormone elevation and the age of the patient. Therefore, the essential difference between thyroid and hyperthyroidism is that thyroid is a glandular organ, while hyperthyroidism is a disease, and hyperthyroidism is a disease caused by the synthesis and secretion of too much thyroid hormone by the thyroid gland due to various reasons.