Cooks use the terms "horseradish" or "prepared horseradish" to refer to the grated root of the horseradish plant mixed with vinegar. Prepared horseradish is white to creamy-beige in colour. It will keep for months refrigerated but eventually will darken, indicating it is losing flavour and should be replaced. The leaves of the plant, while edible, are not commonly eaten, and are referred to as "horseradish greens".