It only help someone to keep living a half, cursed life; not live forever :)

Search for unicorn blood on this

site and you will find more info :)

Okay so I see what you're saying, but from Voldemort's point of view, living a cursed life is better than no life. Even though he wouldn't be a whole person, he should at least be able to exist consciously forever, right?

It only works if you continue to drink it. That's why he attacked at least two unicorns during Harry's first year.

Ah, okay that makes much more sense. Thank you, Banshee!

No problem!