Chaga: The story of a healing mushroom by Markus Eternity

A mushroom that takes two decades to grow, tastes bitter, and has to be chipped off a living tree was never an obvious candidate for the health food aisle. Chaga got there anyway.

For centuries it stayed where it belonged: in Siberian households, where a lump of black fungus went into the kettle the way tea leaves go into a pot elsewhere. Today it turns up in powders, capsules and instant sachets, wrapped in claims that range from the cautious to the absurd. Somewhere between the folk healer's kettle and the marketing copy sits the actual evidence — and that evidence is more interesting than either side lets on.

This book follows chaga from the birch to the cup. It begins with the fungus itself: what it really is, how it lives, why it takes decades to grow, and why the tree matters as much as the mushroom. It moves on to the people who used it long before anyone had a microscope — the Siberian households, the Eastern medical traditions, the reasons a bitter black tea earned a place in daily life.

Then it turns to the laboratory. What have researchers looked for in chaga, and what have they found? The chapters here cover the compounds that draw scientific attention, the studies on inflammation and oxidative stress, the work on immune response, and the questions around the heart, the liver, and the gut. Equally important is what the research does not show — where the studies are small, where they were done in a dish rather than in a person, and where enthusiasm has run ahead of the data.

The final chapters deal with practical matters: how chaga is prepared, why the method changes what ends up in the cup, what is known about sensible amounts, and who should be careful. The book closes with a look at where this strange fungus may be heading, and at what its long, slow life on a birch tree can teach us about patience.

The book is written as continuous prose, without lists or bullet points — meant to be read, or listened to, from beginning to end.

The book is written as continuous prose, without lists or bullet points — meant to be read, or listened to, from beginning to end. Around two and a half hours of listening.