Applied as a compress for piles. Leaves make a soft yellow. The roots were eaten, boiled or roasted, and tasted similar to parsnips. If eaten raw the roots had a crunchy, nutty flavour. Sometimes the roots were dried and ground to make porridge or flour for bread.
Common sorrel is a mordant for black, and the leaves picked in summer produce a blue-green dye.
Leaves of common sorrel used in salads and sauces, and to remove rust stains from linen. Flowers gathered in August. The flowering tops and an alum mordant give a mustard yellow. Fiddle heads combined with alum mordanted yarn produce a corn yellow. Young fronds make an olive yellow.