Viagra has no drug dependence, but may have psychological dependence. Viagra is a drug for the treatment of male erectile dysfunction, the name of the western drug is called sildenafil, after taking the drug can make the penis effective erection, erection hardness is better, can help male patients to complete penile penetration, complete an ideal sexual intercourse. The vast majority of male patients experience impotence, which is caused by mental factors. By taking Viagra you can effectively improve erection, complete sexual intercourse, establish a normal erectile function reflex, and improve the quality of sexual life between husband and wife. Many people eat Viagra after the sexual function improved very ideal, so in the usual sexual intercourse hope to eat Viagra again, this is the so-called mental dependence, the drug itself is not dependent, generally 24 hours the drug is completely metabolized.