Dark green stool usually reflects what you ate rather than a health problem. Chlorophyll from leafy greens like spinach and kale directly colors your feces. Foods with green dyes produce the same effect. When digestion speeds up, bile doesn't fully break down, leaving stool with a greenish tint.
Several medications and supplements shift stool color. Iron supplements commonly darken stool. Antibiotics disrupt your gut bacteria balance, which can trigger green poop. Certain infections, including Salmonella and Giardia, speed up intestinal transit and create the same result.
Illness matters too. Any condition that accelerates digestion, from inflammatory bowel disease to simple food poisoning, can produce green stools. The faster food moves through your system, the less time bile has to oxidize and turn brown.
Most cases resolve without intervention. Track what you ate in the days before noticing the color change. If you recently started iron supplements or antibiotics, that's likely your answer. Reducing leafy greens or waiting for medication courses to finish typically brings stool back to normal brown within days.
Contact a healthcare provider if dark green poop persists beyond a week, especially when accompanied by severe stomach pain, nausea, or ongoing diarrhea. These symptoms suggest infection or digestive illness requiring evaluation. Children and older adults showing these signs need prompt medical attention.
Pay attention to accompanying symptoms rather than color alone. Stool color varies naturally based on diet and digestion speed. Green stool without other symptoms rarely signals anything serious. Your doctor can run tests if genuine concern exists, but in most cases, normal poop will return once your diet or medications change.