Weakness in the elderly is very common and is often seen in clinical work. We believe that it is a normal physiological manifestation that the whole body’s motor function is declining as the function of the nervous system deteriorates in the elderly. Another kind is caused by some diseases, and the more common one in clinical work is electrolyte disorders, especially low sodium and potassium. Due to the control of the diet of the elderly, it is easy to go to the other extreme, that is, low salt and salt restriction, or even close to no salt, and when the patient goes to the hospital, the patient is very low sodium and low potassium. There are some etiologies that are likely to be fatal. There are some elderly people, with some underlying diseases, who take oral diuretics, which also tend to cause electrolyte disturbances. There are also some other drugs with related side effects. In the clinic, I have seen a more common drug called compound licorice tablets, some people cough for a very long time, do not care, and finally the patient came to the hospital because of weakness, the last investigation is to get hypokalemia. So low sodium, low potassium, metabolic disorders are more common. There is also a kind of insensitivity to fever in the elderly, he does not know fever, just weakness and discomfort, then come to the hospital after examination is fever, infectious diseases caused by.