[3] The cap is white, may have fine scales, and is 3 to 12 centimetres (1+1⁄4 to 4+3⁄4 inches) in diameter;[4] it is first hemispherical in shape before flattening out with maturity.

The white flesh bruises a dingy reddish brown, as opposed to yellow in the poisonous Agaricus xanthodermus and similar species.

They may also be distinguished by a white or off-white spore print while mushrooms in the family Agaricacea are dark brown.

A. campestris is found in fields and grassy areas after rain from late summer onwards worldwide.

It is often found on lawns in suburban areas, appearing in small groups, in fairy rings,[11] or solitary.

Owing to the demise of horse-drawn vehicles, and the subsequent decrease in the number of horses on pasture, the old "white outs" of years gone by are becoming rare events.

The mushroom has been reported from Asia, Europe, northern Africa, Australia,[13] New Zealand, and North America.

[14][15] Although edible and choice,[4][16] this mushroom is not commercially cultivated on account of its fast maturing and short shelf-life.

[citation needed] In the past, slices of A. campestris were applied to scalds and burns in parts of Scotland.

[20] Water extracts of A. campestris have been shown to enhance the secretion of insulin, and to have insulin-like effects on glucose metabolism in vitro, although the mechanism is not understood.