Dizziness and blackness in front of the eyes when standing up is a symptom caused by a drop in blood pressure. There is a clinical term called postural hypotension, and the diagnostic criteria for postural hypotension are a drop in blood pressure within three minutes of standing, a drop of more than 20/10 mmHg compared to the blood pressure in a lying or sitting position before standing, or a drop in blood pressure directly below 90/60 mmHg. The older the patient is, the greater the risk of developing postural hypotension, and many elderly people experience syncope mainly due to postural hypotension. In addition, it can also be seen in women, especially young and thin women, who usually have low basal blood pressure, which can become even lower in the standing position, causing dizziness and blackness before the eyes. For this situation, when the position change should be slow, from lying first to sitting, sit for a minute before standing, stand up for a minute before walking, it is not recommended to walk as soon as you stand up, may be in the process of walking, the patient will fall. If hypertensive patients are taking antihypertensive drugs, it is also not suitable to lower the basic blood pressure too low, if too low, the blood pressure will be even lower when the position change, when the possibility of fainting will be greater.