Do vampires poop

Vampires are a work of fiction, and so the whether they digest food and move their bowels or not is also a matter of fiction. This question can be thought of as directly analogous to "does Marge Simpson poop?".

Since Marge Simpson is never shown pooping in any episode of The Simpsons, one could argue that she does not poop. It could equally be argued that, since the character of Marge is a representation of a human being, then she must poop. Both arguments are valid. The difference between Marge Simpson and Vampires is that Marge eats solid food, whereas Vampires (according to most fictional depictions) drink only human blood.

Although blood is primarily water, it also contains protein, iron, fat and many other things that cannot pass through the human urinary tract. Blood does not contain any fibre or other bulking agent, however. If a human drank only blood, they would pass matter from their bowels, although it would likely be of a very thin consistency and hard to control, like diarrhoea.