What happens when a person drinks unicorn blood?

Both Quirrell and Voldemort drank unicorn blood, Quirell for Voldemort's sake in PS/SS and Voldemort in GF. Of couse ... Since no visible harm seems to be inflicted on the person who drinks unicorn blood, we can assume that it's their soul that is damaged. Perhaps .... What happens is that doing that puts a curse on you. read more

I believe Shraddha Dixit sums it up pretty nicely. Unicorns are supposed to be the purest and most innocent among all magical creatures. Harming or killing such an innocent animal is not only an act of deep evil, but also has magical repercussions that go way deeper. read more

Unicorn blood is a thick, silvery substance that runs within a unicorn's veins. The blood of a unicorn can be drunk in order to keep a person alive. However, the act of slaying a unicorn will cause the drinker to suffer a cursed life though the specifics of what this actually entails are not known well. read more

I don't know what would happen in your first scenario, but I feel like drinking the blood of an already dead unicorn would lose its vitality. read more