Hydrazines are nitrogen-containing substances that are found in relatively large amounts (500 parts per million) in the common white mushroom and other mushroom varieties, and that persist after cooking. Mushroom hydrazines cause liver damage and cancer when fed to laboratory mice, but have no effect in rats. It’s not yet clear whether they pose a significant hazard to humans. Until we know, it’s best to eat mushrooms in moderation.
From the book On Food and Cooking (2nd edition) by Harold McGee. © 2004 Harold McGee.
By permission of Scribner, a division of Simon & Schuster, Inc.