When Viagra expires, it should depend on how long it has been expired. The vast majority of drugs expire, there is still a certain role, to make a comprehensive assessment based on the time of expiration. Expired 3-6 months, there is no big problem, only the drug’s role is reduced, after taking the drug will have the same effect. Viagra is a kind of sildenafil, it is a selective type 5 phosphodiesterase inhibitor, after the expiration date to eat can still improve erection, after the expiration of the drug may be 1 tablet of the effective effect, equivalent to the previous 3/4 tablets or half a tablet. It has no special side effects on the body after eating, just a reduction in the effectiveness of the drug.