In the diagnosis and treatment of thyroid disease, doctors often talk about the words “low thyroid” and “low potassium”, but their meanings are completely different and should not be confused. The patient only hears the same two sounds from the doctor, but does not see the specific two words written by the doctor, it is easy to confuse and cause misunderstanding. In my actual work, I often hear some patients confuse the two when describing their condition or consulting about the disease, and the meaning of the expression is unclear, causing misunderstanding. ”Hypothyroidism” refers to low thyroid function, also called hypothyroidism (hypothyroidism for short), and its clinical manifestations are aversion to cold and less sweating, weakness, poor appetite, menstrual disorders, constipation, coarse voice, mucous edema, etc. The thyroid function tests are generally: FT3 low ↓, FT4 low ↓, TSH high ↑. The term “low potassium” refers to the lower than normal concentration of “potassium” ions in the blood, sometimes called “hypokalemia” or “hypokalemia It is sometimes called “hypokalemia” or “hypokalemia”. Its clinical manifestations are nausea, vomiting, anorexia, abdominal distension, mental discomfort, sometimes heart rate disorders, muscle weakness or limb paralysis (sometimes also called “hypokalemia”), and its blood test for potassium concentration is generally lower than normal. Some patients with hyperthyroidism can sometimes have “hypokalemia” and “hypokalemic paralysis”, resulting in muscle weakness or limb paralysis. It is easy to associate with “paralysis”. In fact, at this time, one or two 10% potassium chloride injections are given orally and the patient is allowed to rest in bed for one to two hours, and generally the patient’s symptoms can be improved. Some patients with hyperthyroidism may experience “hypothyroidism” after taking a large amount of medication for a long period of time, which requires stopping or reducing the amount of medication and, if necessary, taking levothyroxine sodium tablets. To clarify “low thyroid” and “low potassium” and to popularize basic medical knowledge is beneficial to our health care.