Hashimoto's thyroiditis is a chronic autoimmune disease and is the most common form of thyroid inflammation clinically. It can be diagnosed through thyroid function tests, iodine-131 uptake tests, thyroid antibody tests, and ultrasound examinations. If there are changes in imaging or if serum anti-thyroglobulin antibodies and anti-thyroperoxidase antibodies are positive, a diagnosis can be confirmed. Regarding treatment, if thyroid function is normal in Hashimoto's thyroiditis, no treatment is necessary, but close monitoring and observation are advised. If Hashimoto's thyroiditis is accompanied by transient hyperthyroidism, symptomatic treatment with beta-blockers can be administered. If there is a decrease in thyroid gland function, thyroid hormone replacement therapy should be initiated, typically with levothyroxine tablets, until thyroid function tests return to normal. Additionally, daily care is important, such as avoiding high doses of iodine intake, maintaining regular sleep patterns, avoiding staying up late, maintaining a positive and optimistic mood, avoiding anxiety and stress, preventing common cold and trauma infections, and ensuring a balanced diet with high protein, low fat, high carbohydrate, and high vitamin content.