Can pineapple consumption cause melena (black stool)?

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Last updated: April 29, 2025 • View editorial policy

From the Research

Pineapple does not typically cause black stool, and its consumption is not associated with an increased risk of gastrointestinal bleeding or black stool. The most recent and highest quality study on the topic of gastrointestinal bleeding is from 2020, which found that the risk of gastrointestinal bleeding increases with combinations of antithrombotic agents and patient age 1. However, this study does not mention pineapple as a cause of black stool. In fact, a 2020 review of pineapple's nutritional values and health benefits found that it is a rich source of minerals and vitamins, and has various health benefits including anti-inflammatory and antioxidant activity 2. Black stool is usually caused by blood in the digestive tract, certain medications like iron supplements or bismuth subsalicylate (Pepto-Bismol), or consuming dark-colored foods like black licorice or blueberries in large quantities. Some key points to consider include:

  • Pineapple is a light-colored fruit that doesn't contain the dark pigments that would turn stool black.
  • If you're experiencing black stool without explanation, it's essential to consult a healthcare provider as it could indicate upper gastrointestinal bleeding, which requires medical attention.
  • Black stool that results from bleeding (called melena) typically has other characteristics like a tarry consistency and distinctive odor.
  • While pineapple contains bromelain, an enzyme that can aid digestion, it doesn't affect stool color.
  • Other digestive effects from pineapple might include mild stomach upset in some individuals due to its acidity or temporary mouth irritation from the bromelain, but color change of stool is not a known effect.

References

Research

Risk of Gastrointestinal Bleeding Increases With Combinations of Antithrombotic Agents and Patient Age.

Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 2020

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