Absolutely, but you have to sneak up behind them unseen until the [Feed] prompt shows up. It's best to target enemies on their own, because anyone facing you or sideways will spot you and attack. If you're a Nightblade however this can be negated with Shadow Cloak, which makes feeding much easier.
Oh and I forgot to add that only non-undead/Daedra humanoid enemies can be fed from. So no feeding on zombies, Dremora, atronachs or critters.
Edited by Ghanima_Atreides on July 31, 2015 1:11PM