Viagra is mainly used for patients with sexual dysfunction, and usually costs more than 1 yuan per tablet. The main function of Viagra is to restore a person's normal sexual function and make you naturally erect when you have sexual impulses. At the same time, Viagra actually has a strong delayed use effect and is a good aphrodisiac. The efficacy of Viagra is safe and effective, but taking Viagra can also cause many side effects, and ordinary people can't take it casually. After taking Viagra, many patients will feel headache, visual disturbance and blurred vision, and some patients will increase the incidence of cardiovascular diseases.