Sudden weakness in the elderly is often caused by the following reasons: First, elderly patients with hypertension, diabetes, hyperlipidemia, coronary artery disease, carotid atherosclerosis, lower extremity atherosclerosis, because these indicators are not well controlled, or not controlled within normal limits, fluctuations in blood pressure, blood sugar, blood lipids and blood supply to the brain, can suddenly cause weakness in the elderly. Second, the elderly unfortunately suffered from new secondary diseases, such as pneumonia, peptic ulcer, tumor of the colon, stomach tumor, renal insufficiency, malnutrition anemia, etc. These causes caused the dysfunction of important tissues and organs, the internal environment metabolism disorder, the elderly will suddenly appear weakness.