Mushrooms are fungi with distinctive fruiting bodies, which are large enough to be seen with the naked eye and to be picked by hand (Chang & Miles 1992). Mushrooms can be broadly grouped into three categories: (1) edible; (2) medicinal; and (3) poisonous. Edible mushrooms (mainly the fruiting body) can be consumed either as flesh (e.g. Agaricus bisporus or button mushroom) or dried (e.g. Lentinus edodes or shiitake) or preserved in other ways. Medicinal mushrooms are fungi not for culinary purposes but contain bioactive components (polysaccharides and or bioactive constituents) that have medicinal application (e.g. Ganoderma lucidum or lingzhi) (Wasser 2010). Poisonous mushrooms have been proved to be or suspected of being poisonous (e.g. Amanita phalloides or death cap). As far as human health is concerned, according to de Román et al. (2006), both edible and medicinal mushrooms may have beneficial effects for humans. In some cases, high levels of heavy metals occur in wild edible mushrooms, and some poisonous species are being mistaken for edible ones. Certain mushroom species contain chemical groups (mycotoxins) such as the cyclopeptide, phenylhydrazine and isooxazole that can be highly toxic to humans (Berger & Guss 2005). This overview focuses on the health benefits of the nutrients and non-nutrient compounds in edible mushrooms, as well as the bioactive chemical components in medicinal mushrooms.