The active ingredient in coffee is mainly caffeine, which has a certain excitatory effect on the central nervous system. Drinking large amounts of coffee for a long time may stimulate the nervous system, including the cerebellum and balance organs causing dizziness and blurred vision. People who have not drank coffee in excess at one time may cause enhanced vasoconstriction, even resulting in increased blood pressure and increased heart rate, which may also cause short periods of dizziness, blurred vision, dizziness and headaches, closely related to the effects of coffee. Long-term coffee drinkers will not appear obvious dizziness phenomenon, the body has gradually adapted, if they have high blood pressure, coronary heart disease, cerebrovascular disease, is not suitable for long-term coffee consumption, there may be head discomfort.