Wider and shorter
Your large intestine is a wide tube that goes around your small intestine like a picture frame. It runs up the right side of your belly, across the top and down the left side.
In a grown-up it's about 5 feet long. That's much shorter than the small intestine, but it's two to three times wider. That's why it's called large.
Most of it is called the colon. Near the start is the little pouch called the appendix. At the very end is the rectum, where poop waits until you go to the bathroom.
The water soaker
When leftovers arrive from the small intestine, they're still runny and wet. The large intestine slowly soaks up most of that water and puts it back into your body.
Things move slowly here, often for a day or more. The longer leftovers stay, the more water gets soaked up.
That's why poop can be soft or hard. Drinking water and eating fiber help keep it soft and easy to push out.
Trillions of tiny helpers
Your large intestine is home to trillions of bacteria, about as many as all the other cells in your body! These are helpful microbes (MY-krobes), tiny living things too small to see.
Together they're called your gut microbes. They munch on fiber, the tough part of plants that your body can't break down by itself.
In return, they make some vitamins, like vitamin K, and help keep harmful germs away.
Fruits, vegetables, beans and whole grains are full of fiber, your gut microbes' favorite food.
How poop is made
Poop is mostly water. The rest is bits of food your body can't use, like tough plant parts, plus lots of bacteria and old cells from your gut lining.
Poop is brown because of bile from your liver. Bile starts out yellow-green, and your gut bacteria change it to brown.
When the rectum fills up, it tells your brain, 'Time to go!' It's best to go when you feel the urge instead of waiting.
Everybody poops: kids, grown-ups, astronauts and puppies too. It's one of the most normal things a body does!
Toots are normal
Your gut bacteria make gas while they eat fiber. That gas has to go somewhere, so out it comes as a toot!
Everyone passes gas, usually several times a day. It's a sign your gut microbes are busy.
Beans, broccoli and other healthy foods can make extra gas. That's OK. Your microbes are having a feast.
Most of the gas doesn't smell at all. The stinky part is a tiny bit of gas with sulfur in it, the same stuff that makes rotten eggs smell.