It’s probably something you ate
The most common reason for green stool is a dietary habit or change. Food that can cause green stools include:
kale
spinach
broccoli
blueberries
Dark green vegetables and green powder supplements contain a lot of chlorophyll, the chemical that allows plants to make energy from the sun. This can turn your Cleveland Brown into a Green Bay Packer. That doesn’t mean there’s something wrong. Keep eating those greens!
Bile pigment
Bile is a fluid made in your liver and stored in your gallbladder. This fluid naturally has a green-yellow color. When bile combines with foods you eat, the bile helps to increase the efficiency of pancreatic lipase so your body is able to break down more fat from the diet. This allows more fat to be absorbed into your body in the small intestine.
However, your body must break down bile so it can be excreted as waste. Normally, this is accomplished by traveling a pathway through your intestine. Sometimes when you have diarrhea or other stomach cramping, bile can’t be broken down as quickly. The result can be poop that appears green in tint because of the natural green color of bile salts in your body.