The Agarikon family has strong anti-inflammatory properties with antibacterial and antiviral properties. Researchers tested 11 strains of Agarikon found in North America and discovered strong activity against swine flu (H1N1), bird flu (H5N1), and herpes (HSV1, HSV2) viruses. The ancient Chinese believed that Ganoderma mushrooms promoted longevity, and the Greeks called Agarikon the elixir of long life.
Stamets' studies with U Illinois also demonstrated some level of effectiveness against tuberculosis, confirming folklore, as well as cowpox, swing and bird flu, and the virus that causes herpes.
Despite that history, most of the research I can find on this particular mushroom is by Paul Stamets, as here:
Agarikon grows to resemble a very large beehive and grows like a fruit hanging from the places where branches connect to trunks on old tall trees. Historians have noted that Native Americans mashed the fungus and used it as a medical remedy for a variety of ailments. Stamets notes that even the ancient Greeks knew about the medicinal qualities of agarikon, suggesting in an early text that it was useful for combating a host of diseases. Thereafter in Europe and the U.S. it became known as a treatment for several lung ailments including consumption (tuberculosis). Stamets has been working with the University of Illinois to more closely study the medicinal benefits of the fungi, starting shortly after 9/11. He and the team there found that administration of agarikon showed anti-tubular activity when testing against the tuberculosis bacteria, reaffirming ancient beliefs. They also reaffirmed that eating the fungi can reduce inflammation and that it can be used to help combat both bacterial and viral infections. Thus far, he reports, research has shown strong activity against cowpox, swine and bird flu and the virus that causes herpes. In some instances, he notes the effectiveness was better in some cases than conventional therapies. He claims also that thus far there is no indication that agarikon is toxic to humans.
Given its demonstrated level of effectiveness as an anti-viral, anti-biotic, I've wondered about cultivating the Agarikon; unfortunately this is something that's only found in old-growth forests.