Compounds having unique antiviral and antibacterial properties are prepared from medicinal mushroom mycelium, extracts and derivatives. The compositions are derived from Fomitopsis, Piptoporus, Ganoderma, Inonotus, Trametes, Pleurotus, and blends of medicinal mushroom species and are useful in preventing and treating viruses including Poxyiridae and Orthopox viruses, flu viruses including bird flu (H5N1), SARS and Hepatitis C (HCV), as well as infections from Mycobacterium tuberculosis, Staphylococcus aureus and Escherichia coli.