Viagra is a therapeutic drug for the treatment of erectile dysfunction, and this drug is relatively safe to use. Since its introduction in 1998, it has shown a good safety profile in various countries around the world, in various populations, both older and younger, and in people with organic diseases. Some data show that various adverse reactions occur after the use of Viagra, especially damage to the heart and blood pressure, which is actually often caused by improper use by patients or improper selection of drugs. In general, the adverse effects of Viagra on the human body include headache, nasal congestion, facial flushing, and in some cases, indigestion, all of which are extremely short-lived and mild, and can be self-recovery without any treatment. Therefore, as long as Viagra is used within the normal safe dose, the safety of this drug is guaranteed.