An annual, it belongs to the Goosefoot family growing up to 1 metre tall, the stems usually multi-branched. The common names derive from its use to feed hens and the shape of the leaves; others from where it is found; around dung heaps, cultivated arable land and on waste ground.
The matt, grey-green leaves are oval to diamond shaped, have a powdery coating and are paler underneath. They can be used as a pot herb, in soups or fried. Before spinach was introduced to Britain the leaves were boiled and eaten with butter especially in monasteries where it was cultivated, giving rise to some of the alternate names.
Some species of Chenopodium are thought to be toxic in large quantities due to the presence of saponins, but they are poorly absorbed and cooking breaks them down. (The saponins are also present in beans, some of which must be cooked to destroy them, eg. kidney beans.) There is also some oxalic acid present, but this too is destroyed by cooking. Conditions such as arthritis, gout and kidney stones may be exacerbated by consuming this herb, but a decoction made from the stems was taken in some places in Ireland for rheumatism.
Fat Hen was taken to North America as a pot herb, but it is now widespread.

The fatty seeds can be eaten whole or ground into a flour for bread, cakes, and gruel; they taste similar to buckwheat. Deposits of gathered seeds have been recovered from Bronze Age settlements in Britain. Another member of the Genus is Chenopidium quinoa or plain Quinoa, which is considered a superfood.

Hoe or hand pull before flowering - easily uprooted.
Weedkillers to use:-
Paraquat, Diquat by contact action.
A residual herbicide prevents germination in paths and gravel.
MCPA and 2,4-D are both effective.

Follow these links for further details on Weeds, Weed Removal and Weed Prevention.