Poop Decoder
Why is my poop green?
Usually something you ate, or speed. Green poop mostly comes from green food, green or blue food dye, or food that rushed through too fast for bile to turn brown. On its own, it's rarely a worry.
Worry level Low
Usual cause food or fast transit
Lasts until the cause passes
What usually causes it
Bile starts out green
Your liver makes greenish bile. As it travels through your gut, it's broken down step by step until the final pigment turns stool brown.
Fast transit skips the brown
When food moves through quickly, as with diarrhea, bile doesn't have time to break down and stays green. Green stools carry more bile acids than brown ones.
Greens and dyes
Leafy greens like spinach carry chlorophyll, which can tint stool green. Some green food dyes contain copper-bound chlorophyll and can turn it dark green.
Sources: The Conversation, Why is my poo green?; MedlinePlus, Black or tarry stools.