Viagra refers to the drug sildenafil, and sildenafil is generally not allowed after brain vascular bypass surgery. After the brain bypass surgery, the body is relatively weak, can not be too early to have sex, at least one to three months of recovery period, the physical condition will gradually improve. Sildenafil is a drug that promotes penile erection in men, and after taking the drug, it will lead to central nervous system excitement and accelerated blood circulation, which is not conducive to post-operative recovery, and in serious cases, it will also lead to ischemic shock and hypertension. Therefore, for the sake of health, it is not recommended to take sildenafil after brain vascular bypass surgery. Patients after brain vascular bypass surgery should pay attention to more rest and avoid strenuous exercise.