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Why is poop brown?

The short answer

The color comes from your old red blood cells. Your body breaks them down into a yellow substance called bilirubin, and tiny bacteria in your gut turn it brown.

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Poop gets its brown color from your old blood cells. Tiny helpers in your gut finish the job.

Where does the brown start?

Red blood cells wear out after about 4 months. Your body breaks them down and makes a yellow substance called bilirubin.

Illustration from the video: Your body breaks them down and makes a yellow substance called bilirubin.

How does it reach your poop?

Your liver mixes it into bile, a liquid that helps you digest food. Bile flows into your gut, where tiny bacteria turn it brown.

Illustration from the video: Bile flows into your gut, where tiny bacteria turn it brown.

Why does poop change color?

Some foods can change the color, like beets or leafy greens. If food rushes through too fast, poop can come out green.

Illustration from the video: Some foods can change the color, like beets or leafy greens.

Illustration from the video: If food rushes through too fast, poop can come out green.

Illustration from the video: Very pale, black or bright red poop should be checked by a doctor.

One more thing

Without enough bile, poop can turn pale, almost like clay. Very pale, black or bright red poop should be checked by a doctor.

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