The blood vessels of the human body are mainly divided into resistance vessels and volume vessels, and different dilated blood vessels will have different symptoms and manifestations. Resistance vasodilatation may cause low blood pressure, dizziness, fainting, etc. Volume vasodilatation may cause abdominal distension, indigestion and other symptoms. 1. Resistance vasodilatation: (1) Resistance vessels mainly include small arteries, micro arteries and branch vessels of small arteries. When resistance vessels are dilated, the afterload of the heart is reduced, that is, the resistance of the heart to ejection of blood is reduced, and the myocardium can be rested and cardiac function can be restored, and at the same time, the blood supply to the organs and tissues is increased, but it will lead to a drop in blood pressure. (2) Since the brain is the most sensitive to ischemia, resistance vasodilatation causing cerebral ischemia will produce dizziness, fatigue, nausea, and even fall and fainting may occur. 2. Volume vasodilation: (1) Volume vessels mainly refer to the venous system, which mainly plays the role of blood storage. When volumetric vasodilatation occurs, the blood storage volume increases, the return blood volume decreases, and the cardiac preload decreases, but it will significantly slow down the blood flow rate, which can easily lead to thrombosis. (2) Volume vasodilatation causes circulatory stasis, which is most evident in the gastrointestinal tract, where abdominal distention, indigestion, and other gastrointestinal stasis can occur, and if deep vein thrombosis occurs, it can also lead to lower extremity edema. It should be noted that excessive vasodilatation and constriction are detrimental to health, and patients with cardiovascular disease need to follow the doctor’s instructions for regular treatment.