Okay, I've been thinking. If Spike is able to eat food and not get sick, and throwing it up. That got me wondering what happened to the food once it entered the stomach? That lead to my next thought that the stomach must be working to house the food, or it would be like a food traffic jam in there for years of eating food. So there is stomach acid in there to break down the food. But then that means some sort of digestion is at work and he ends up expelling the food later. The same goes for his drinks.

That also brings me to the whole sex thing, if his body wasn't functioning in some manner I'm sure he would be able to produce semen either. So for a vampire they aren't completely undead their bodies are working to some point. Does that make sense?

makes sense to me

Okay, here's what I think.  In reality- when a body dies, all the *stuff* gets expelled.  It just takes longer.  I see no reason for it not to work that way with a vampire.  The vampire is an animated corpse, so the body would function to a certain degree; that would include sexual fuction.

But as far as "live" semen...I don't think that would be possible.  That's why "Connor" was concieved under the magic of Wolfram and Hart.

That's my two cents, anyway.

FetchingMadScientist

What goes in must come out.  That's just the way it works.  With the exception of blood, which is the only nutrition a vampire really needs and gets circulated into their body to become their blood, anything else they eat/drink would have to be eliminated.  I think a lot of authors just ignore that because it's "icky."  But if their bodies can produce other things, like sexual fluids/semen, saliva and tears, it would stand to reason that they can produce waste.  I'm also of the opinion that vampires sweat.  We see it in the show several times, but it's largely ignored in fanon, again, I believe because of the "ick" factor.  For example, when Spike and Buffy are fighting in the church in season 2, Spike's forehead is all sweaty, and in season 5 when Spike and Harmony are having sex (y'know, when he's fantasizing about fighting with Buffy) they're both all sweaty.  And if they can sweat, that means they can smell.  Example, in season 7 when Spike is still kinda crazy, and Willow gets captured by that demon, Spike tracks her, and Buffy says something along the lines of, "Spike follows the irresistable smell of blood and we follow the fairly ripe smell of Spike."  So yeah.  I think it's a fanon thing.

I agree: What goes in must come out. 

According to canon, vampires sweat, produce saliva, cry (okay, maybe only Spike cries...all the time), etc.  They have sex, so they must lubricate, or else it would be pretty painful for everybody.  Based on Angel telling Buffy that he can't have children, I'd think that male vampires still produce seminal fluid, but not the actual sperm since that is the life force.  Or perhaps the sperm are all dead.  Like shooting blanks.

If they can do all of those things, then I'd think that they eliminate the food and liquids that they consume.  Perhaps they only do so when they've consumed people food (I feel like I'm talking about my cat).  So, Angel would almost never have to go to the bathroom, whereas Spike, would go as much as any human.  They don't ever explain how the undead eliminate on the show, but living people almost never use the bathroom on TV either.

I did read a fic (can't remember the title) once that had an interesting theory: The undead body's molecular structure is constantly struggling to stay together.  All of the undead molecules constantly vibrate in an effort not to fall apart into their natural dead state--dust.  The vibration uses the energy from the blood and people food to keep the body together and causes the body to sort of hum with energy.  When the vamp dies, the body's molecules fall apart into dust.  I thought that it was a freaking cool idea :-)

 The undead body's molecular structure is constantly struggling to stay together.

That is pretty cool. Reminds be of chim. class where my teacher told us about how our molecules vibrate to keep us to gether. And he said something like when we did the molecules stop moving. So I think that would make sense with the animated corpse.

I'm with the whole sweat, tears, saliva, etc. So see I'm happy I brought this topic up, yay, lol. Thanks for the ideas guys.