The causes of low blood pressure include heart disease, postural low blood pressure, postprandial low blood pressure, low blood pressure caused by medication, and hormone secretion abnormality. 1. Heart disease: for example, myocardial infarction, heart failure, bradycardia is the main cause of cardiogenic hypotension, and the symptoms of hypotension can only be improved by treating the primary disease. 2. Postural hypotension: the blood pressure will change from sitting to standing position, from lying to standing position, the systolic blood pressure will decrease and diastolic blood pressure will decrease in less than three minutes, and accompanied by the typical symptoms of low blood pressure. 3. Postprandial hypotension: systolic blood pressure falls within two hours after eating compared with that before meals, commonly seen in Parkinson’s and diabetic patients. 4. Low blood pressure caused by taking drugs: often take diuretics, tricyclic antidepressants, anti-Parkinson’s drugs. 5. Hormone secretion abnormality: low thyroxine secretion in hypothyroidism, the patient’s basal metabolic rate decreases, and at the same time, manifested as a decrease in cardiac output, slowing down of the heart rate caused by low blood pressure; There are many causes of low blood pressure, if there is fainting and blurred consciousness, you need to go to cardiovascular medicine and emergency department in time to confirm the diagnosis through physical examination or laboratory tests, and treat the symptoms after clarifying the cause of the disease, so as to avoid delaying the condition.