Medicinal mushrooms have a long history of use for modulating immunity, protecting against cancer, and just generally strengthening the system (see, for instance, Rebecca's post on shiitakes). I spend long hours all year round looking for polypores (shelf-mushrooms, generally) in the woods around here, and there is one that can be found and harvested any time of year: the Chaga mushroom, also known as the Clinker polypore, or Inonotus obliquus in the old tongue. Folk medicine, especially in Siberia where these birch-loving fungi grow in abundance, has long regarded the Chaga as a premiere anti-cancer remedy. I generally find it growing on members of the Betula genus (birches, most often golden birches), often ones that are a bit sick. The Chaga almost looks like a cancerous outgrowth from the bark of these trees - an interesting signature. Some have speculated that the fungus acts somewhat as a processing lab for the betulin in birches, a compound that has received much attention as an anti-cancer agent.
I have used Chaga extensively, along with other mushrooms, to support comprehensive protocols for cancer management. Recently, scientific evidence has been building on this particular fungus. Hopefully soon we will get some human data, but for now here's a brief roundup:
Anti-tumor activity of two isolates from Chaga (animal model...)
Antimitotic activity of aqueous extracts of Inonotus (in vitro)
Antioxidant effect of Inonotus (in vitro)
Melanin complex in Chaga (biochemical analysis)
(Melanin has received attention as a potent botanical immunomodulator, perhaps linked to some of Echinacea's immune-enhancing effects).
I use a custom-made double extract of Chaga in my practice. The mushrooms are harvested, stored for a few weeks (not really to dry them, just to get them a bit 'cured') and then divided into two equal portions. You will need a good, sharp saw to cut it in half, and then a heavy hammer / hatchet to chop them up into manageable chunks (about the size of an almond). I steep the first half in a menstruum (solvent) made of 70% alcohol, 20% water, and 10% vegetable glycerin (in a 1:5 ratio, weight of Chaga to volume of menstruum). This tincture favors the phenolic compounds listed in the first study above. After 4-6 weeks of steeping, I strain the tincture and set it aside.
The second half (saved now for many weeks) I place in a crockpot with twice the volume of water as the volume of the strained tincture, and set it to a slow cook for about 48 hours. The goal is to cook it down and strain it so the amount of water extract equals the amount of strained tincture (add water during the cooking process if necessary). Finally, let everything cool down to room temperature, and whisk the two extracts together. Final alcohol percentage is 35%. The color: mahogany brown, beautiful and rich. The flavor: bittersweet, deep and woody, with overtones of humus. Strong healing medicine!