mushrooms cannot be separated from the environment considering their major function in the national biological cycles, they biosynthesize their own food from agricultural crop residues, which, like solar energy, are readily available; otherwise, those byproducts and wastes would cause health hazards while the spent compost/substrate on which the mushroom grew could be used as fodder for livestock, as a soil conditioner and fertilizer, and in environmental bioremediation. Mushrooms can be used as food, tonics, medicines, cosmeceuticals, and as natural biocontrol agents in plant protection with insecticidal, fungicidal, bactericidal, herbicidal, nematocidal, and antiphytoviral activities. Their use, function and effect cannot be overemphasized & it continue to benefit mankind since time immemorial.