Hypothyroidism refers to hypothyroidism, and the occurrence of high and low thyroid function is mainly considered to be related to the influence of drugs, diet and other factors. 1. Influence of medication: During the application of medication for hypothyroidism, overdose or underdose of medication can lead to the phenomenon of high and low hypothyroidism. 2. Dietary influences: For hypothyroidism caused by iodine deficiency, insufficient or excessive intake of iodine may also lead to the phenomenon of fluctuating high and low hypothyroidism. 3. Other factors: For secondary hypothyroidism, such as pituitary tumors, improper control of the primary disease may also cause this phenomenon. If the above phenomenon occurs, it is recommended to consult a doctor in time and follow the doctor’s instructions for treatment.