The next time you ponder your poop before you flush, one thing to keep in mind is that your feces passed through a lot of important organs on their way out. (And if you don’t take a peek, well, congratulations on your moral superiority, I guess?) So it might be possible that your stool can tell you when there’s something wrong with the squishy internal Rube Goldberg machine that converts food into feces.

Ponder your poop before you flush

I have a lot of questions about what this external nugget of evidence says about the inner workings of my body: is that the shape it’s supposed to be? When did I eat that corn? Why is it blue? (That only happened once.)

The quick and dirty version of the digestion process starts as soon as we take a bite. Little molecular wrenches called enzymes start dismantling our food in the mouth, then the stomach. In the small intestine, enzymes do even finer work — breaking down fats, proteins, and starches into molecules small enough to pass through the intestine’s walls and into the bloodstream. That’s how you absorb the food’s nutrients. Muscle contractions called peristalsis push the food — now a soupy, messy slop — along to the large intestine, where water is sucked back into the body. What you’re left with is, usually, is a somewhat solid mélange of indigestible food leftovers, microbes, dead cells, and all sorts of waste products our bodies need to expel. The stool hangs out in the rectum before squeezing out through the anus.

Once the poop is in the toilet, what can it tell you about your body? Since the porcelain bowl isn’t a magic mirror, I quizzed gastroenterologist Justin Sewell from the University of California, San Francisco while he grabbed a quick lunch on the other end of the phone.

A photo posted by Nabhan Al Abdullatif (@nabhan_illustrations) on Feb 6, 2013 at 10:42am PST

Earth tones are healthy — but so are lots of other colors

Poop can come in a rainbow of colors depending on what you eat. But earth tones like brown, yellow, and green are the most common, Sewell says. These muddy hues are the result of mixing digested food with broken down bits of dead red blood cells that get dumped into the small intestine along with bile, an enzyme produced by the liver to digest fats.

There's a huge range of normal

If your poop falls outside this range of shades (like, say, blue), it’s not necessarily unhealthy. But if your poop is gray, black, red, or maroon, those colors could be signs of a health problem. Pale or gray could mean that something is preventing bile and its accompanying red blood cell waste from reaching the small intestine. That could be from a problem anywhere in the liver, the gallbladder (which stores bile), and the connecting ductwork. Often, people with gray poops show other signs of liver problems, like jaundice.

Black, red, or maroon-hued poop can all be from bleeding. Tarry and sticky stools usually suggest bleeding from the stomach or upper small intestine — like from an ulcer, for example. Dark red or maroon poops could mean bleeding in the upper colon or lower small intestine. Red diarrhea could be due to an inflammatory bowel disease like Crohn’s disease or ulcerative colitis — or it could mean that your colon is infected with bacteria like certain strains of E. coli. And bright red blood on the toilet paper could be due to hemorrhoids — itchy, swollen veins in the rectum or anus that bleed. That’s the much more common, and much less scary option: because it could also be from polyps or colon cancer.

Poop can come in a rainbow of colors

But remember, poop is food waste so you might just be seeing the results of something you ate. Iron supplements or Pepto-Bismol can also make your poop black, and beets can make your poop red. (It also turns your pee red. I thought I was dying the first time this happened.)

There’s no ideal poop shape

When I create a perfect, uninterrupted log I feel victorious — like I peeled an apple without breaking the spiral of skin. But Sewell tells me that my quest for the perfect poop is misguided: There’s no such thing.

"I’ve had people bring me pictures of their poop and say ‘This is not right, it’s supposed to be a perfect, smooth log shape.’ And yes, for some people that’s normal but for other people, that’s just not the way their body works," he says. "There’s no ideal poop."

"There’s no ideal poop."

Poop types and shapes can grouped into seven categories in the Bristol Stool Scale, which describes the range of imaginable stools — from hard little rabbit pellets (type one — a sign of constipation) to watery diarrhea (type seven — which could be due to anything from an infection to having just gone for a run). As long as your poop falls into types two through six on the Scale, you’re probably doing just fine.

"Anywhere from formed logs to soft and falling apart is fine — and that just depends on individual people’s bodies and their diet," Sewell says. If it’s hard or sticky, however, you might want to add fiber and water to the menu. If it’s mushy or watery, drink more water to rehydrate.

Food bits are fine, but lots of them is weird

Sighting food in poop isn’t unusual, Sewell says. But pay attention to how the food looks. It’s totally normal to find pieces of corn kernels, for example, which have indigestible bits made of a plant fiber called cellulose. "If you eat a bunch of greens, you’re going to see pieces of partially digested plant material come out," Sewell says. And the chunks can be bigger or smaller depending on how well you chew.

But if your poop is almost entirely composed of recognizable food bits, it could be signs of a digestion problem. Your gut might be squeezing food through too quickly to get properly digested. Anything from parasites, to certain types of gastrointestinal infections, to even irritable bowel syndrome and severe celiac disease can get peristalsis moving faster than it should. So if what comes out strongly resembles what went in, maybe you should see a doctor.

Mucus and fat aren’t okay

If you see mucus on your poop, that can be a sign of an autoimmune disease or an infection. But what does mucus even look like when it’s coming out of an orifice other than your nose? It’s white, semi-solid, and stringy, Sewell says. Like egg drop soup, he adds.

Seeing that in the toilet bowl suggests inflammation, most likely in the lower gut. The inflammation could be from ulcerative colitis or Crohn’s disease — or from some kind of parasitic, viral, or bacterial infection.

A photo posted by Nabhan Al Abdullatif (@nabhan_illustrations) on Jul 11, 2015 at 3:42pm PDT

Be on lookout for fat in poop as well. A fatty stool usually floats and can leave an oil slick on the surface of the water. After you flush, there might be orange ring of what looks like pizza grease that lingers around the bowl. Like when you’re cooking something oily, Sewell says, "and you pour out the water, and there’s a rim of fat that sticks to the edge of the container."

Fatty poop can come from a number of things — including diet pills like Alli that can make fat leak out your butt. It can also be a sign of pancreatic or liver disease, because it means the enzymes they produce that should be breaking down fat aren’t doing their jobs. Intestinal disorders like Crohn’s disease or celiac disease can cause this, as well.

So what does your poop say about you?

The main thing to keep in mind is that there’s a huge range of normal. That also includes the frequency with which you poop — generally, anything less than three times per week is constipation, and anything more than three times a day is too frequent. Most people poop one to two times a day, or once every other day, Sewell says. Variation in urgency is common, too — having to go right now isn’t unusual, but if that’s a constant sensation, you may want to check in with a doctor.

"Pay attention — but don’t obsess."

"I think it’s healthy for people to look at what they produce, note any major changes, and ask their doctor about it," Sewell says. "People do obsess over having, they want the perfect shape poop, they want it harder, they want it softer. It’s not really much under your control besides eating more or less fiber, or consuming more or less water. So pay attention — but don’t obsess."

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