Low diastolic blood pressure can be caused by physiological factors and disease factors. Physiological factors are mostly found in malnutrition and weaker people, while disease factors are found in decreased blood volume, organic heart diseases, and so on. 1. Physiological reasons: it may be due to malnutrition, weak physical condition, poor vascular compliance or old age, the elasticity of large arteries decreases, compliance decreases, so it leads to the decline of diastolic blood pressure. 2. Pathological causes: common blood volume reduction, the causes include traumatic bleeding, upper gastrointestinal bleeding, nausea and vomiting leading to excessive fluid loss or fever and sweating without timely rehydration and so on. Organic cardiac diseases that lead to a decrease in diastolic blood pressure, such as pericarditis and aortic valve insufficiency. If the diastolic blood pressure is persistently low, it is recommended to go to the hospital in time for examination to clarify the cause of the disease. It is recommended to pay attention to a light diet, low-salt and low-fat diet, which is conducive to good health.