In the past year, we have encountered more and more patients with so-called “Hashimoto’s thyroiditis” in our clinical work or in our online Q&A sessions, and some doctors have even given patients 2 pills of Eugenol daily with normal thyroid function and ordered them to take it for life. Thankfully, the treatment of Hashimoto’s thyroiditis is currently symptomatic, and replacement therapy is usually necessary only in the presence of hypothyroidism, and hyperthyroidism can be treated as hyperthyroidism, which leaves room for proper management. So what is Hashimoto’s thyroiditis? Hashimoto’s thyroiditis, also known as chronic lymphocytic thyroiditis and commonly referred to as Hashimoto’s disease, is an autoimmune disease. The disease is usually seen in women between 30 and 50 years old, with an insidious onset and a long, slow progression. Most people seek medical attention for enlarged thyroid gland, while a few seek medical attention for low thyroid symptoms (fear of cold, facial edema, swollen feeling in the limbs and numbness in the hands and feet, etc.). On physical examination, the thyroid gland is diffusely or restrictively enlarged, with a hard texture like rubber, clear borders, no tenderness, and a smooth surface; some patients have a nodular thyroid gland, and a few have an atrophied, hard thyroid gland due to fibrosis. Patients do not have enlarged lymph nodes in the neck, and some may have mucinous edema of the extremities. Thyroid function and related antibody tests: The results of the tests vary depending on the course of the disease. (1) Normal or elevated serum T4 and T3 in the early stage, but mostly normal TSH; decreased serum T4, normal or decreased T3, and elevated TSH in the later stage; (2) Normal or increased thyroid iodine uptake in the early stage, and decreased iodine uptake in the later stage; (3) Significantly elevated titers of anti-thyroglobulin antibody (TGAb), anti-thyroid microsomal (TMAb), or peroxidase antibody (TPOAb), which may last for several years or more than 10 years. In clinical practice, the author found that typical Hashimoto’s disease, in addition to having clinical thyroid palpation-specific manifestations, has synchronized very high antibody levels, with anti-thyroglobulin antibodies > 10,000 IU/mL and peroxidase antibodies > 2,000 IU/mL; (4) increased sedimentation up to 100 mm/h, decreased serum albumin, and increased r-globulin. Treatment: The current treatment of Hashimoto’s thyroiditis is based on symptomatic treatment, and those with normal thyroid function can be observed on a follow-up basis. If you have hyperthyroidism, you can take anti-thyroid medication and levothyroxine tablets at the same time. Short-term hormone therapy or surgery can be used only when the enlarged thyroid gland is obviously accompanied by pressure symptoms. However, if there are nodules in the thyroid, it is best to review them every six months. When the disease progresses and hypothyroidism develops, treatment with levothyroxine tablets in full doses (50-200ug of eugenol) should be started, starting with small doses in older people. The conventional hormone therapy used in the past was not effective in stopping the progression of the disease, but caused new damage to human health due to its high side effects. Therefore, early application of hormones has been abandoned in favor of thyroxine replacement therapy after the development of hypothyroidism.