The lack of strength of legs in old age may be related to low potassium, lower limb vascular disease and ischemic encephalopathy, which can be treated with medication and surgery. 1. Low potassium: Due to the deterioration of digestive system, endocrine system and other functions of the body, the elderly may suffer from low potassium and other electrolyte disorders, resulting in lack of strength in the legs, which can be treated with medication such as potassium chloride extended-release tablets. 2. Lower limb vascular lesions: due to the degeneration of organs and tissues and the reduction of exercise, the elderly may suffer from venous thrombosis and vascular stenosis, which may lead to leg weakness due to the change of hemodynamics of the lower limbs, so drugs such as rivaroxaban can be given to treat this condition, and when the condition is serious, vascular stenting can be used as a vascular stenting operation. 3. Ischemic encephalopathy: Ischemic encephalopathy occurs in the elderly, when the brain tissue that manages the sensory movement of the lower limbs is ischemic and hypoxic, there can be a lack of strength in the legs, and in severe cases, there is also the possibility of paralysis, coma, and so on, and can be given aspirin, clopidogrel and other medications, and in severe cases, it is necessary to perform cerebral vascular thrombus removal and other surgeries. If the symptoms of weak legs are not relieved after lifestyle modification, you should consult a doctor in time to clarify the cause of the disease and carry out treatment under the guidance of the doctor. All of the above medications should be used under the guidance of a physician, and should not be used without authorization.