If the patient is black in front of his eyes when he suddenly sits up: 1, the most common factor is upright hypotension, which belongs to the performance of abnormal blood pressure regulation and is common in the elderly, and the patient will have dizziness and blackness when he suddenly sits up; 2, for the patients with insufficient blood volume, for example, dehydration caused by heatstroke or nausea, vomiting and other factors, extensive bleeding, burns, which triggers the insufficiency of blood volume, there will be There will be blackness in front of the eyes when sitting up; 3, adverse reactions after taking drugs, such as patients applying a large number of vasodilators, diuretics, antihypertensive drugs and antidepressants for treatment will also have the above situation; 4, the regulation of the homeostasis of the internal environment is reduced, such as long-term bed-ridden patients, febrile patients, combined with chronic cardiac insufficiency, neurological insufficiency, there will be the above clinical manifestations.