The distinctive odor of feces is due to bacterial action. Gut flora produce compounds such as indole, skatole, and thiols (sulfur-containing compounds), as well as the inorganic gas hydrogen sulfide. These are the same compounds that are responsible for the odor of flatulence. Consumption of foods with spices may result in the spices being undigested and adding to the odor of feces. The perceived bad odor of feces has been hypothesized to be a deterrent for humans, as consumption or touching it may result in sickness or infection. Of course, human perception of the odor is a subjective matter; an animal that eats feces may be attracted to its odor. from http://en.wikipedia.org/wiki/Feces#Odor

@rpmpseudonym : Oh… gotcha. (:

My dog might not agree with this question.

it’s relative. it’s smell is quite similar to a lot of recent questions on fluther.

LMAO

Mine doesn’t stink. I tell my wife that all the time. She doesn’t believe me.

AGAIN LMAO

For the same reason decaying bodies smell “bad” to us: people who hung around either often became sick and died during the early stages of animal evolution, so those to whom decay and feces smelled bad had more children, and eventually we had a species to all of whom decay and feces smelled bad.

I don’t even poo, as you can see I’m not human so I wouldn’t know.

ROTF!

And the really weird thing is that when you eat food that smells bad; then your poo smells good!

So we don’t eat it. It smells bad to us because it is capable of making us sick, and more people would eat it if it smelt tasty.

What does it even mean to say it “smells bad”? Doesn’t that just mean that we are programmed to react adversely to that particular odor? The odor makes us avoid it, and therefore to avoid possibly harmful exposure to it. People who avoid it are more likely to survive and pass on the trait of not liking the odor.

[Edit] Hmm, I see that I’ve just given the same answer as @CaptainHarley, in different words.

My answer is the same as @AstroChuck my dog loves baby diapers covered in it, and he tears apart the bags of used diapers (and used cat litter) if they don’t get taken directly to the trash can. I can always tell when my grandsons need changed, because the dog starts following the around with his nose in their butt.

And as long as we’re on this train of though, why does Asparagus make your pee smell funny?

Evolution.

@Jeruba

[ smille ] Well, you COULD do a lot worse than to answer the same way I did! ; ))

Shit happens!

Since this answer has been satisfactorily answered (basically, we’ve evolved to find certain smells repulsive for health reasons), why asparagus makes your pee smell.

my dog loves used sanitary products too!

My asparagus patch has just one tiny little half inch sprout. This is my first year for harvest and can hardly wait!

Poo smells bad because, well, it’s poo.

if poo smelled good…..dumb people would eat it.

Because of a poor diet. Poo should never smell badly. When it does, it is the symptom of a poor diet and/or dehydration. Drink more water for a week and notice a change once convinced begin to change your diet specifically reduce your intake of animal proteins. I recommend a weekday vegetarian diet. You’d be amazed at how much undiscovered good food is out there.