Cenforce pill has an active compound called Sildenafil Citrate.

Sildenafil treats erectile dysfunction by inhibiting the activity of phosphodiesterase type-5, a substance that is naturally present in the penis.

While engaging in sexual activity, Sildenafil Citrate assists in widening (relaxing) the blood vessels.

Consequently, there is an increase in the volume of blood flowing through the penile area of the body. This mechanism assists men in getting and maintaining a solid erection.

Both are different brand names for   Cenforce 100  . They work in the same way and remain active for almost the same time 4-6 hours. The only difference is in cost where the Viagra pills are a bit cheaper than Cialis.