Why Does Poop Smell?

Why is MY poop so smelly?


The good news is everyone’s poop tends to smell.  The bad news is… well… poop still smells. There are a lot of answers to the question “why does poop smell?” and we’ve tried to cover most of them here.  Chances are good you’ll read one of the reasons for excessive bowel movement smells and go “ah, that makes sense!” 

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Before we start though, bear in mind — while you’re bearing down — that most bowel movements include passing gas as well as poop.  The smell from your farting will typically spread faster than that of any poop sitting below the waterline in your toilet.

So now, with open minds and plugged noses, let’s make some sense of our bathroom scents.

It’s something you ate:  high-fat foods

Almost any smell related to your pooping output is related to your digestive system input… and most of our input is food.  A high-fat diet can overpower your digestive system, and your body may have trouble breaking down all the fat you’ve eaten.  If the fat doesn’t get broken down first, it can’t be absorbed by the body further down the digestive line. The result is basically fat going through the colon undigested, giving you a diarrhea with it’s own special name — steatorrhea.  And yes, it smells as bad as is sounds.

It’s something you ate:  high-sulfur foods

Pretty much any time you put sulfur together with a bodily function, you’re going to get a bad odor.  Sulfur will definitely make your poop smell. Although sulfur is a required part of our overall diet, too much of it increases sulfur gas which not only comes out as farts, but is released from the poop it gets trapped in.  Foods that are high in sulfur include eggs, meat, dairy, and cruciferous vegetables.

It’s something you ate: lactose

If you’re lactose intolerant, it means the lactose itself doesn’t digest, so it fires through the intestine, and comes out smelly — often as diarrhea.

It’s something you swallowed:  medication

Very rarely — if ever — will the side effects description on your prescription include “may make your poop smell”.  The fact is, many medicines, prescription or off the shelf, will affect the speed at which your food gets digested, have an effect on your digestive bacteria, prevent absorption of some food ingredients, or have smelly ingredients in them.  All of these will make your poop smell — as well as introduce other issues such as diarrhea or constipation.

It’s something you swallowed:  supplements

Basically, you can think of supplements as a potential mix of everything that can make poop smell.  We already mentioned foods rich in sulfur and many supplements — including garlic, glucosamine, and chondroitin — are the same.  Your colon will take the sulfates and turn them into sulfide gases which are held in your poop until released into freedom (and also released as smelly farts).

It’s something you have:  infection or disease

If your poop smells and you think you’ve eliminated everything on the above list, you might have some kind of gut infection, digestive disease, or some other illness.  For example, if you don’t have a high-fat diet, but still have the kind of smelly diarrhea you’d expect from it, it could be the little bit of fat you’re eating is still not being absorbed because of pancreatic diseases or Celiac disease.  Another possibility is an infection in the colon, for example, Clostridium difficile. If you suspect your poop smells because of any kind of illness, it’s time to set aside any potential embarrassment and visit a doctor. A doctor visit is even more important, if not critical, if the smell is accompanied by blood in your stool.  We’re not talking about spots of bright red blood on your toilet paper (that’s a different topic) — blood from the gastrointestinal tract usually appears black in color, and the texture is often sticky.

It’s something you drank: alcohol

Sorry drinkers… here’s yet another bad thing alcohol will do to you — make your poop smell horrible.  By now you’ve heard many times that alcohol will affect your brain and liver, but it affects other organs as well, including the poop-related stomach, small intestine, and large intestine.  The alcohol will mess up the movement of the intestines as they try to digest food, and interfere with the intestinal wall’s ability to absorb nutrients. Booze will also have a negative effect on prebiotics and probiotics in your digestive system.

On top of all the above, alcohol is full of sulfate, which your bowels turn into sulfide gases, which turn your bathroom into a gas chamber.

Drink alcohol… expect a smelly colon cocktail later.

It’s something you ate: artificial sweeteners

That sorbitol might help you lose weight, but maybe not in the way you expected.  A side effect of Sorbitol is that it helps move water into the large intestine, acts like a laxative, and creates smelly diarrhea.

Is there a pooping question we haven’t answered?

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