Green poop

Green poop usually comes down to one of two things: something green or dyed in what you ate recently, or stool that moved through too fast for bile to finish turning brown. Leafy greens, green or blue food coloring, iron supplements and antibiotics are the most common explanations. Mayo Clinic counts green among the typical stool colors. If you feel fine, a green day is almost always food.

See more than color: Stoolio's Color Assessment includes green as one of its six shades, read alongside your Bristol type and 12 visual readings, so you can see whether green arrived with a fast, loose day or on its own. Your first three scans are free.

Why can poop be green?

Bile starts out as a yellow-green fluid and is chemically changed from green to brown as it travels through the gut. Anything that interrupts that process, or adds a stronger green on top of it, shows up in the bowl. Cleveland Clinic's gastroenterologist puts the odds plainly: if you feel perfectly fine and do not have diarrhea, a different-colored bowel movement is most likely linked to something you ate.

Common explanations

• Leafy greens. The chlorophyll that makes kale and spinach green can do the same to your poop.
• Food coloring. Green dye in drink mixes and ice pops, and even blue or purple dyes, which can turn greenish as they mix with digestive juices.
• Iron supplements, which can turn stool dark green or even blackish.
• Antibiotics, which can change the gut's bacteria and add a greenish tint.
• Stomach bugs and diarrhea. Bacterial and viral infections, and parasites such as Giardia, can cause green diarrhea as bile rushes through unchanged.
• Gallbladder removal, which can temporarily send more bile into the gut.

Conditions such as irritable bowel syndrome, Crohn's disease and ulcerative colitis can also cause green stool, though Cleveland Clinic's expert notes these are possible but not the norm.

Foods that can turn poop green

Spinach, kale and other leafy greens top the list, but Cleveland Clinic also names blueberries and other blue or purple produce, avocados, green apples, honeydew, hemp seeds, basil, cilantro, parsley, matcha and pistachios, plus anything with green, blue or purple food dye. A food-driven tint should disappear within a day or two once the source has passed.

Transit: when speed is the reason

This is the most common non-food reason. Mayo Clinic explains that when food moves through the large intestine too quickly, as with diarrhea, bile does not have time to break down completely, and stool stays green. That is why green often arrives with a loose, fast stool, like a Type 6 or Type 7 on the Bristol chart. When transit slows back down, the brown returns.

When green is worth a clinician's ear

Green on its own is rarely a concern. Check in with a clinician if green stool lingers, or comes with belly pain, weight loss, bleeding, fever or vomiting. If it arrives with diarrhea, the usual adult guidance applies: see a doctor if diarrhea lasts more than two days, or right away with a high fever, blood, black stool or signs of dehydration. One thing to know: very dark green can look black in poor light, so if you are unsure, look again in bright light.

What Stoolio looks at visually

Green is one of the six shades in Stoolio's Color Assessment, alongside pale, light brown, brown, dark brown and very dark. Because the same scan also reads your Bristol type, consistency and fragmentation, it shows whether green came with a fast, loose stool or a perfectly ordinary one, which is the difference between "transit" and "that spinach salad." Add a note about what you ate and the pattern gets clearer. See the full poop color chart.

Sources

1. Mayo Clinic. Stool color. 2024.
2. Cleveland Clinic Health Essentials. Why Is Your Poop Green? 2026.
3. Cleveland Clinic. What Does My Stool (Poop) Color Mean?
4. Cleveland Clinic Health Essentials. Can Food Change the Color of Your Poop? 2025.
5. AAP HealthyChildren. Stools: Unusual Color (symptom checker).
6. NIDDK. Symptoms & Causes of Diarrhea.