Subacute thyroiditis (subacute thyroiditis) is a common and easily overlooked thyroid disorder. Many patients with subacute thyroiditis are often referred to the endocrinology clinic because they have lost weight and have menstrual disorders, and the disease is confirmed. The thyroid gland is one of the most important endocrine organs in the human body. It is located below the laryngeal node, below the middle of the neck, in the shape of an H. It is wrapped around the trachea like a beautiful bow, and the thyroid gland is easily accessible and therefore easily injured. The thyroid gland weighs only 20-30g and is the “engine” of the body’s metabolism. Thyroid hormone levels affect the basal heart rate and body temperature, the speed of gastrointestinal motility, the growth and development of the body, and the normalization of menstruation. It can be said that the thyroid gland affects the metabolism of many systems and cells in our body. The thyroid gland is composed of follicles and parafollicular cells of different sizes. The follicles are surrounded by a single layer of cubic follicular epithelial cells, which are the “warehouses” for the synthesis and secretion of thyroid hormones. When the level of thyroid hormone synthesis and secretion is just right, the body’s metabolism is in a dynamic balance, but under the action of various pathogenic factors inside and outside the body, abnormalities in thyroid function can occur, and subtle changes in the body can occur. Subthyroiditis is a metabolic inflammation of the thyroid gland caused by a viral infection. Typically, subthyroiditis is divided into a thyrotoxic phase, a hypothyroid phase, and a recovery phase. In the early stage of the disease, when the viral infection attacks the thyroid follicles, thyroid hormones are released into the bloodstream, resulting in destructive thyrotoxicosis, where T3 and T4 levels increase and TSH decreases. At the same time, the thyroid gland itself is exhausted by the frequent viral attacks, and at one point, the iodine uptake rate is reduced, resulting in a “separation” between thyroid hormone levels and iodine uptake by the thyroid gland. This is an important feature that distinguishes subthyroiditis from other thyroid disorders. As the disease evolves, the thyroid follicles are depleted of their thyroid hormone stores, and the thyroid gland becomes devastated, with various repair projects and reconstruction tasks to be carried out, and the thyroid gland’s ability to take in iodine and synthesize thyroid hormones is severely deficient. This is followed by the complete repair of thyroid follicular cells and the recovery period, when blood sedimentation, C-reactive protein, thyroid hormone levels and iodine uptake return to normal, and the patient’s abnormal symptoms disappear. Because the symptoms of subthyroiditis are not specific, they make correct identification more difficult. When patients with respiratory tract infections are seen, careful examination of the thyroid gland and careful screening are required to prevent underdiagnosis or misdiagnosis of subthyroiditis. In clinical practice, in the hyperthyroid phase, once the patient has palpitations, hand tremors and other thyrotoxic manifestations, oral beta-blockers such as propranolol can be administered to regulate the heart rate, and in the TCM phase of heat toxicity, the patient can be given the “Subthyroiditis 1” formula to clear heat and detoxify swellings and disperse nodules. If too many thyroid follicles are destroyed and not fully repaired later, very few patients with subthyroiditis will develop permanent hypothyroidism, requiring long-term oral levothyroxine tablet replacement therapy. From this perspective, early application of glucocorticoids can effectively inhibit metaplasia, reduce the extent of thyroid destruction, and accelerate the progress of follicular repair, which can prevent and treat permanent hypothyroidism. Glucocorticosteroids have certain side effects and are prone to relapse after discontinuation. Therefore, after the heat and pain have subsided, you can use Chinese medicine to nourish yin and clear heat, reduce swelling and disperse nodules with “Yajiaoyi 2” to reduce the toxic side effects of western medicine and reduce the relapse rate. Most of them can recover on their own, which is one of the few curable diseases in the spectrum of endocrine diseases. The early identification of the disease is crucial, and the combination of traditional Chinese medicine and western medicine has the effect of reducing toxicity and increasing effectiveness, which can shorten the course of treatment and reduce recurrence. Patients usually pay attention to strengthening exercise and constantly improving their immunity to effectively avoid respiratory infections, thus preventing the recurrence of subluxation.