今注目を集めている Can Blueberries Cause Black Poopについて、多角的な視点を分かりやすく掲載しています。

Short answer: Yes, they absolutely can. If you’ve just demolished a pint of fresh or frozen blueberries, your body is about to give you a colorful (or rather, colorless) report card. Think of it as a tiny, edible prank your digestive system plays on you.

Those deep-blue pigments are packed with anthocyanins, the same antioxidants that make blueberries a superfood. When these pigments meet your gut acids and enzymes, they can oxidize and turn your stool a shade of dark greenish-black—perfectly harmless, but definitely alarming at first glance.

Don’t Panic, Just Pass the Blueberries

Here’s the key: blueberry poop is not the same as dangerous black poop. Real medical black poop (called melena) looks like sticky, tarry coffee grounds, and it usually signals bleeding in your upper digestive tract. Blueberry poop? It’s more like a smudge of dark art—a bit messy, non-sticky, and likely to resolve within 24–48 hours after you stop munching.

So before you rush to WebMD in a cold sweat, ask yourself: Did I eat a bowl of blueberries for breakfast, a handful as a snack, and maybe another bowl after dinner? If the answer is yes, you’re probably just giving your gut a delicious, antioxidant-rich workout.