The plague of modern humankind has been the common cold. In current times, however, more serious viral infections, some leading to certain death, have plagued society, including hepatitis B (a liver disease transmitted through transfusions, the use of unsterile needles, or other blood-to-blood contact) and HIV (the virus that causes AIDS). Whether shiitake can cure the common cold is doubtful, but an extract of it, called LEM (Lentinula edodes mycelium) shows promise as a treatment for more serious viral infections, including hepatitis B and HIV.

You may have encountered mushroom mycelium while digging in rich soil; it is a stringy, weblike material that looks like a rotted root system. When temperature, moisture, and other conditions are right, the mycelium develops fruiting bodies, or the portions we call mushrooms. In Japan LENI has been the focus of many studies.

Hepatitis B: Trials of LEM at 16 clinics in Japan during the 1980S involved an unspecified number of patients with chronic hepatitis B. The studies showed that LEM may cause the body to produce protective antibodies, so a follow-up study was conducted. Forty people with chronic hepatitis B took 6 grams of LEM orally each day for four months. Hepatitis B symptoms were alleviated in all of the patients, and the virus was inactivated in fifteen.