(a) Subacute thyroiditis, also known as De Quervain’s thyroiditis (thyroiditis) or giant cell thyroiditis. It occurs after a viral infection of the upper respiratory tract, with symptoms of a pre-cervical mass and thyroid pain. It is usually seen in women aged 30-40 years. Clinical manifestations: sudden swelling, hardness, difficulty swallowing and pain in the thyroid gland, duration of the disease is 3 months. Diagnosis: History of upper respiratory tract infection 1-2 weeks prior to the disease. A high basal metabolic rate but a significant decrease in thyroid uptake of 131 iodine was demonstrated 1 week after the disease. This separation phenomenon and the effectiveness of prednisone therapy contributed to the diagnosis. Treatment: Prednisone 5mg 4 times daily, reduced after 2 weeks, for 1-2 months, with the addition of dry thyroid preparations effective, and radiotherapy if relapse after discontinuation of the drug. Antimicrobials are ineffective. (b) Chronic lymphocytic thyroiditis, also known as Hashimoto (Hashimoto) goiter, is an autoimmune disease and is the most common cause of goiter combined with hypothyroidism. The disease is most often seen in women aged 30-50 years. Clinical presentation: painless diffuse goiter, symmetrical, hard, smooth surface, with hypothyroidism, larger goiter may compress the trachea. Diagnosis: Enlarged thyroid gland, low basal metabolic rate, decreased thyroid uptake of 131 iodine, combined with multiple antithyroid antibodies in the serum may aid in the diagnosis. A puncture biopsy can confirm the diagnosis. Treatment can be long-term with dry thyroid preparations, which are mostly effective. Biopsy or surgery should be performed to rule out malignancy in those with symptoms of compression.