Birch Polypore: What Worked, What Lasted, and Why
Birch polypore, also known as Fomitopsis betulina or Piptoporus betulinus, is a bracket fungus that grows almost entirely on birch trees. It is found across the northern hemisphere, including northern and eastern Europe, Scandinavia, Russia, Siberia, and parts of North America. People have noticed and used this fungus for thousands of years, not by accident, but because of how it behaves, where it grows, and what it does.¹
When birch polypore first appears, it looks nothing like the hard bracket people usually imagine. At the earliest stage it is bright white, very soft, and spongy, often looking like foam or a cluster of smooth bubbles pushed out from the bark. It can look almost artificial, as if it has been piped onto the tree. At this stage the whole fungus feels fleshy and even, not layered. As it grows, the surface tightens and firms, the shape slowly becomes more like a loaf or hoof, and the colour shifts from white to cream and then pale grey. Over time it becomes rubbery and eventually cork-hard as it dries out.²
These changes mattered. Very young birch polypore was mainly used for medicine or for dressing wounds. Once it had firmed up but was not yet fully hard, it could be sliced and dried to make a leather-like material. This was used for sharpening razors and knives, which is why the fungus is often called “razor strop fungus.” It worked well because the inside of the fungus is very even and fine, without grit. Instead of scraping metal away, it gently straightened and polished the blade edge. Barbers, hunters, soldiers, and travellers valued it because it was light, durable, and did not rot easily. It also needed no tanning; drying alone was enough.³
Birch polypore was also used for wound care. Slices of the fungus were placed directly on cuts, ulcers, or infected skin. It absorbs moisture, slows bacterial growth, and forms a breathable protective layer. These same qualities made it useful as tinder and helped explain why it lasts so well in harsh conditions.⁴
Across northern and eastern Europe, birch polypore appears again and again in folk medicine as a “cleansing” or “corrective” fungus. It was used especially for digestive trouble and for parasites. In Russian, Baltic, Finnish, Sámi, and Central European traditions it was usually prepared as a long-simmered decoction rather than a quick tea. Dried pieces of the fungus were gently heated in water for hours, sometimes kept at the edge of a hearth all day without boiling hard. This slow method mattered, because the bitter compounds were drawn out gradually.⁵
The bitterness was important. Bitter medicines were believed to drive out worms, correct digestion, and make the gut an unpleasant place for parasites to live. Sweetening was usually avoided. The drink was taken in small amounts, often once or twice a day, commonly on an empty stomach. Birch polypore was not taken as food and was never swallowed raw.⁶
Treatment was short. Most accounts describe courses of three to seven days. Birch polypore was not meant to be used constantly; it was described as drying and corrective, not nourishing. After a course, people were often given broths, milk, or grain porridge to rebuild strength. The expected effects were mild loosening of the bowels, changes in stool, and sometimes visible parasites. Strong purging was not the goal. The fungus was valued because it worked steadily rather than violently.⁷
This careful, restrained use helps explain why birch polypore appears so consistently in traditional medicine. Modern chemistry partly supports these observations. Many of its compounds act mainly in the digestive tract and are poorly absorbed into the rest of the body, which fits the idea that it worked locally rather than systemically.⁸
Birch polypore use often followed the seasons. Late winter and early spring were considered risky times, after months of limited food and long indoor living. People believed parasites were more common then, and mild cleansing remedies were more likely to be used. It was also taken after illness or hunger, when the body was thought to be weaker and more vulnerable.⁹
The most famous early example comes from the Copper Age ice mummy known as Ötzi. When his body was discovered, pieces of birch polypore were found among his belongings. They were not random fragments; they had been dried, pierced, and threaded, suggesting they were meant to be carried. At the same time, Ötzi’s intestines showed infection with whipworm. Because birch polypore is not good food and does not grow casually along alpine routes, researchers have suggested it was carried for medicinal reasons, likely to help with parasites. This interpretation is cautious rather than absolute, but the context makes it a strong possibility.¹⁰
Birch polypore was also used on animals. In forested parts of northern and eastern Europe it was given to pigs, goats, sheep, and sometimes dogs when worms were suspected. Preparation was simpler than for people. The dried fungus was crushed or shaved and either boiled into a strong liquid or mixed directly into feed. Amounts were judged by the size of the animal rather than measured, and treatment was brief, often just a few days. Farmers watched closely and stopped once the animal’s condition improved. It was not used routinely, only when needed.¹¹
In the Scottish Highlands, where birch was common, birch polypore became one of the most trusted remedies of this kind. It was not the strongest option available, but it was reliable, local, and gentle enough to use carefully. It was especially used for children, dogs, goats, and sheep.¹²
Stronger bitters existed. Tansy was known as a very powerful dewormer and was widely feared as well as respected. It was used only when infestation was obvious. Wormwood had a similar reputation across Europe. Other Highland remedies included bog myrtle, which was used to drive out worms and insects; juniper, used more gently as part of mixtures; and garlic, which was extremely common and believed to discourage parasites even though it was not bitter in the same way.¹³
Seen together, these patterns show why birch polypore mattered. It was not chosen because it was dramatic, but because it worked within the limits of everyday life. It was available year-round, acted predictably, and could be used with care rather than fear. That balance is what allowed it to remain part of ordinary medicine for so long.¹⁴
1. Allen, D.E. & Hatfield, G., Medicinal Plants in Folk Tradition. Timber Press, 2004, pp. 27–31, 178–181.
2. Ryvarden, L. & Gilbertson, R.L., European Polypores, Vol. 1. Fungiflora, 1993, pp. 346–349 (Fomitopsis betulina morphology and distribution).
3. Holtzapffel, C., Turning and Mechanical Manipulation, Vol. II. London, 1846, pp. 871–879, 892–899, 905–910.
(Principles of stropping, polishing, and edge alignment using organic materials.)
4. Hobbs, C., Medicinal Mushrooms. Botanica Press, 1995, pp. 178–181.
5. Beith, M., Healing Threads: Traditional Medicines of the Highlands and Islands. Birlinn, 1995, pp. 92–99, 126–129.
6. Allen & Hatfield, 2004, pp. 41–44, 214–217.
7. Beith, 1995, pp. 96–99; Allen & Hatfield, 2004, pp. 215–217.
8. Wasser, S.P., “Medicinal Mushroom Science,” International Journal of Medicinal Mushrooms, various articles 2010–2015; overview discussion pp. 1–8 depending on paper.
9. Allen & Hatfield, 2004, pp. 33–35 (seasonal use of vermifuges).
10. Capasso, L., “5300-Year-Old Intestinal Parasites in the Ice Man,” The Lancet 352 (1998): 1861–1863.
11. Mathias, E. & McCorkle, C.M., Ethnoveterinary Medicine: An Annotated Bibliography. FAO, 1989, pp. 14–18, 47–52;
Lans, C. et al., Journal of Ethnobiology and Ethnomedicine 3:2 (2007), pp. 1–7.
12. Synthesis of Beith 1995, pp. 90–101; Allen & Hatfield 2004, pp. 212–218.
13. Beith, 1995, pp. 101–108; Allen & Hatfield, 2004, pp. 220–225.
14. Synthesis of all ethnographic sources above.