Out of Korea comes a new and increasingly popular medicinal mushroom known as Phellinus linteus. It does have a rarely used English common name, Black Hoof Fungus. But you are more likely to hear it referred to by its Japanese name as Mesima.
Common to southern United States and Southeast Asia, Phellinus linteus is a polypore on hardwood trees such as poplar, oak and mulberry. 
Most medicinal mushroom species used today in America came to us via China or Japan. Phellinus linteus is a break from this trend, as it first became popular in Korea where it’s commonly used to complement traditional cancer treatment.
From there, the fame of Phellinus linteus has spread across the globe. Doctors all over the world now use it as an immune enhancer [2-11], particularly to prevent cancer metastasis. [5,10,12-17] In addition to Korea, Phellinus linteus is today also increasingly popular in the U.S., Japan, and the Middle East from Turkey to Israel.
Perhaps it all got started when one of the first Korean studies on Phellinus linteus in 1996 reported that it exhibited a wider range of immunostimulation and antitumor activity than polysaccharides isolated from other medicinal mushroom species. 
Years later, American world-renown mycologist Paul Stamets helped deepen our understanding of Phellinus linteus when he published a comparative analysis with the most common medicinal mushroom species: Agaricus blazei, Lion’s Mane, Chaga, Reishi, Maitake and Cordyceps. 
Phellinus linteus had a stronger effect than any of them on the part of the immune system known as macrophages. The activity of this type of white blood cell increased by 5,700% when Phellinus linteus extract was administered in an amount equivalent to 3,750 mg for an average size adult (165 lbs). 
Macrophages as part of the human immune system can be a two-edged sword. They may devour cancer cells, but can also stimulate cancer growth. The published research on Phellinus linteus indicates that it activates the cancer-fighting properties of macrophages, not the cancer-stimulating properties. [8,14,19,20]
Additional reports have been published on cases of “spontaneously” regressed cancers, where the patients reported having used Phellinus linteus by their own choice:
1. A Japanese article from 2004 reported a “dramatic remission of hormone refractory prostate cancer achieved with extract of the mushroom, Phellinus linteus.” 
2. A Korean journal published a paper in 2005 which reported on a “spontaneous regression of a large hepatocellular carcinoma with skull metastasis.” The 65-year-old patient had “ingested mushroom called Phellinus linteus for one and a half years.” 
3. And then one year later, in 2006, another Japanese article was published on “a case of spontaneous regression of hepatocellular carcinoma with multiple lung metastases.” The 79-year-old patient had been taking an extract of Phellinus linteus Mycelium for a month. When examined by his doctor 6 months later, his tumors had disappeared. 
This article is for informational purposes only. It is not intended to diagnose, treat, cure or prevent any disease. The mushroom Phellinus linteus has not been approved by the FDA for medicinal use. Always consult a licensed medical practitioner before using any herb or mushroom medicinally.