Subacute nonsuppurative thyroiditis (De Quervain’s thyroiditis) is also known as nonspecific granulomatous thyroiditis. It is often secondary to upper respiratory tract infection or mumps. The cause may be a viral infection that destroys part of the thyroid follicle, releasing colloids as if they were foreign bodies, causing a foreign body reaction within the thyroid tissue. Clinically, some patients have an acute condition with elevated body temperature, swelling and pressure pain in the thyroid gland; the pain often spreads to the ear and occipital area and worsens when swallowing. However, most patients have a milder disease, with only a hard thyroid gland and light pressure pain. Blood sedimentation is significantly increased, but white blood cell count is normal. The duration of the disease is usually about 3 months, and thyroid function does not decrease after healing. In terms of treatment, prednisone has obvious efficacy, pain is quickly relieved and swelling subsides, but it is also prone to recurrence, then prednisone can be used again with the addition of dry thyroid tablets. Antibacterial drugs are not effective.