What are the ingredients in Viagra?

Sildenafil is the active ingredient.

Other ingredients are:

Tablet core:

microcrystalline cellulose, calcium hydrogen phosphate (anhydrous), croscarmellose sodium, magnesium stearate

Film coat:

Hypromellose, titanium dioxide (E171), lactose monohydrate, triacetin, indigo carmine aluminium lake (E132)