Weakness and weakness in the legs may be a precursor to cerebrovascular disease, hypokalemia, herniated lumbar discs, hypoglycemia and diabetes. 1. Cerebrovascular diseases: such as cerebral hemorrhage, the main manifestations of which are distorted eyes and mouth, limb paralysis, speech disadvantage, and in severe cases, coma, etc., which may also cause the phenomenon of weakness in both legs. 2. Hypokalemia: a pathological condition in which the potassium ion content in the blood is lower than the normal range (<3.5mmol/L), which is a very common electrolyte disorder in clinic. The most common manifestation is muscle weakness, which usually occurs first in the limbs, and then can be extended to the whole body and even the respiratory muscles, which may also cause the phenomenon of weakness in the legs. 3. Lumbar disc herniation: the lumbar disc may compress the nerves, resulting in numbness of the limbs, thus causing weakness of the legs. 4. Hypoglycemia: the glucose content in the blood is lower than normal, there may be palpitations (rapid heartbeat, often accompanied by panic), trembling, sweating, hunger, and even coma and other symptoms, which may also cause the patient’s legs to become weak. 5. Diabetes mellitus: a group of metabolic diseases characterized by chronic hyperglycemia, long-term metabolic disorders due to defects in insulin secretion and utilization, which can cause multi-system damages, may also cause the phenomenon of the patient’s legs weak and feeble. There are many other causes of weakness in the legs, you should go to the hospital in a timely manner to identify the cause of the disease, active treatment, so as not to delay the condition.