Revered in the Orient for two millennia as the "Mushroom of Immortality," Ganoderma has been demonstrated to have a therapeutic effect on 16 out of 17 areas of health in Paul Stamets' chart on medicinal mushrooms. That's more than any other mushroom species.
Known in Tibet as Ling Chi, Ganoderma has a long history of use against high-altitude sickness and infections.  As a tribute to its gift of healing, or maybe just because it is beautiful in its own right, many Buddhist shrines and temples contain engravings of the Ganoderma mushroom.
Something you'd probably never hear an ancient healer refer to is that Ganoderma extract is exceptionally high in anti-oxidants. And perhaps the resulting protection from free radical damage may have something to do with its acclaimed anti-aging effect. [34, 35, 36, 37, 38, 39, 40, 41]
Another possible contributing factor to the acclaimed anti-aging properties of Ganoderma may be its anti-inflammatory compounds known as triterpenoids. [42, 43, 44, 45] (Alcohol extracted.) After all, inflammation is involved in many of our most common ailments, from bronchitis, asthma and atherosclerosis , to allergies, arthritis [47, 48, 49, 50, 51] and the common cold. The triterpenoids of Ganoderma extract have even tested positive with inflammatory conditions of the prostate  and brain. 
Allergies and inflammations are the results of an exaggerated immune response. So it has surprised researchers to discover that while Ganoderma extract calms the out-of-control immune response in cases of inflammation, it actually improves a healthy immune response. [48, 54, 55] It's even demonstrated some inhibitory effect on the replication of HIV in mother and daughter lymphocytes. 
Lung and heart functions are also important as we age. Research on Ganoderma extract has indicated that it may help increase the oxygen absorbing capacity of the lungs , blood profusion of the heart muscle, and decrease blood pressure.  In other words, its an energizing tonic, which may be why it has also been demonstrated as having an effect in cases of chronic fatigue. [59, 60]
Like several other medicinal mushrooms, Ganoderma also contains anti-tumor compounds. Research on Ganoderma extract has yielded positive results on cancers of the cervix, prostate, liver, lungs, bone and blood. [61, 62, 63, 64, 65] Two studies indicate that this effect is secondary, by way of stimulating the body's own immune system and cancer fighting mechanisms. [66, 67]
Two Chinese studies have shown Ganoderma extract to have liver protective effects in cases of post-hepatic cirrhosis  and chronic hepatitis .
One study showed it to have a restorative effect on certain functions of the spleen.  A variety of skin disorders have been treated with powdered Ganoderma,  including rashes from poison ivy and oak, although this claim still may need to be conclusively verified. 
Paul Stamets lists the following additional therapeutic areas of potential use for Ganoderma extract: Candida; Diabetes / Hyperglycemia; Cholesterol; Kidney Function; Respiratory System; Nerves; and Stress. 
Note: The statements on this page have not been evaluated by the Food and Drug Administration. This article is not intended to diagnose, treat, cure or prevent any disease. Never use any herb (or mushroom) except as advised by a licensed medical practitioner.
Credits: Thank you, Paul Stamets, for research references.