Why Is My Poop Green? The Age-Old Question, Answered

Written by Wendie Trubow, M.D. MBA
Wendie Trubow is a functional medicine gynecologist with almost 10 years of training in the field. She received her M.D. from Tufts University.

Photo by Tatjana Zlatkovic

I was never a huge fan of fluorescent, brightly colored foods, but I distinctly remember the day that I swore them off completely, thanks to my oldest daughter. She was our firstborn, so of course we obsessed over everything, including her food. She was 3½ at the time and called me in to wipe her after she used the bathroom. I looked into the toilet and practically had a heart attack: The poop in the toilet was bright green. I was horrified, convinced she was mortally ill.

But no, she wasn't dying and is currently a thriving 14-year-old. She was simply not digesting the food coloring found in the green cookies she had eaten the day before.

What does it mean when your poop is green?

There are many reasons poop can be green, one of which is eating food with green, purple, or black food coloring in it, which can come out in poop as a green color. When you see this, it means you're not digesting the artificial colors very well. The best solution to this is to eat super clean, drink lots of water, and not challenge the gut with dyed foods.

Photo: Alberto Bogo

Even if you're eating well, certain unprocessed foods—like kale, broccoli, spinach, and even blueberries—can cause your poop to be green (although blueberries often cause black stool). If you eat chlorophyll, it can also turn your stool green. If you notice your poop is green and you're not consuming dyed food, this is great news because you are doing an amazing job of eating your veggies. Keep up the healthy work!

Diarrhea, which is a rapid transit of stool through the large intestine, is another main reason poop can be green in your toilet bowl. This happens because when you have diarrhea, the bile from your gallbladder doesn't have time to break down completely, so it comes out green. Most cases of diarrhea from food poisoning will pass within 24 to 48 hours, although you can feel out of whack intestinally for a while afterward. It's important to drink lots of water when you have diarrhea so that you don't get dehydrated. Otherwise, as long as your diarrhea is getting better over a few days, it's fine to wait it out.

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Is green stool ever a cause for concern?

Of course, the thing that everyone worries about is: "Do I have cancer?!?" While it's possible, it's not likely that green poop is a sign of cancer. Cancer often bleeds, and one sign of cancer can be rectal bleeding, or black, tarry stools.

But there are a few situations in which green poop would be a reason for concern. If you have green poop for longer than 72 hours, it might mean you have C. difficile—an infection that typically happens after a long course of antibiotics or in someone with immune system dysfunction. It's often characterized by frequent, green, very smelly diarrhea and often has a low-grade fever associated with it. If this sounds like you, then this is a reason to consult with your physician.

More likely, though, if you're having green poop, it's because you either ate something dyed, are having diarrhea (sometimes foods dyed with food coloring can increase your diarrhea, too), or because you're just rocking your veggie intake. But, as always, if you're worried, definitely consult with a physician for an evaluation.

Ready to learn more about how to unlock the power of food to heal your body, prevent disease & achieve optimal health? Register now for our FREE web class with nutrition expert Kelly LeVeque.

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