Book excerpt: Backed by centuries of use by Asian herbalists and doctors and now by solid scientific research, the supplemental use of medicinal mushrooms has gained tremendous popularity. Among their many benefits, medicinal mushrooms have been shown to restore the competency of the immune system and to improve the outcome for people with a variety of serious illnesses, including cancer, hepatitis, and other conditions where effective nontoxic treatment options are limited. This book describes the most common supplemental medicinal mushrooms-including maitake, reishi, shiitake, and cordyceps-and their best clinical uses. Choosing products that match the potency of the supplements used in the supporting research requires a basic understanding of quality and potency and how the descriptions on the labels relate to the strength of a product. Therefore, this book also provides the basic knowledge needed to make the best choices to achieve the desired and highest therapeutic results. Book jacket.