Vasoconstriction is commonly caused by several reasons: first, due to cold, emotional and other stimuli that cause vasoconstriction. Second, due to special diseases, such as Raynaud’s syndrome, which can cause spasm and constriction of blood vessels under the stimulation of certain specific conditions, resulting in ischemia in the blood supply area of blood vessels. Third, under the effect of smoking or some special drugs, it may cause vasoconstriction. Vasoconstriction can bring about a local deficiency of blood supply, and after a longer period of time even cause organic changes in the arteries, and sometimes thrombosis. So when vasoconstriction occurs, vasodilation and antiplatelet therapy can be given to prevent thrombosis and improve the vasoconstriction.