Lamb's lettuce is a flavorful salad green native to the temperate zones of Europe. In addition to being found in the wild in many parts of Europe, the green is also sold in markets, especially in the spring, when the tender young shoots are the most flavorful. Outside of Europe, lamb's lettuce can sometimes be a bit challenging to find; for people who are having difficulties, several seed companies sell lamb's lettuce seeds which can be cultivated at home. Like other greens, lamb's lettuce is very easy to grow at home, although it will go to seed quickly in warm climates.

Several different species in the Valerianella genus are known as lamb's lettuce, and there are numerous alternate names for this green, which can add to consumer confusion. It is also sometimes called field or corn salad, in a reference to the fact that it often grows wild in cultivated fields. The “lamb's lettuce” name appears to stem from the fact that it tastes best during lambing season, and some people also call it lamb's tongue, because the leaves resemble small tongues. It can be found on restaurant menus as mâche.

When fresh and young, lamb's lettuce has a slightly nutty, tangy flavor. Some people consider it a borderline bitter green because of the tang, and older greens definitely verge on the bitter. Field lettuce can be used in salad mixes, or eaten on its own; some cooks also steam it and use it like a vegetable. If lamb's lettuce is cooked, it is usually just briefly wilted to retain the flavor and nutritional value. The nutty flavor pairs well with a range of dressings and other ingredients.

Like many zesty-flavored foraged greens, lamb's lettuce has a high nutritional value. It typically provides several vital minerals and nutrients, including vitamins C, E, and B9, along with beta carotene and essential fatty acids. Commercially cultivated lamb's lettuce may not be as nutritionally rich, depending on farming practices, but it is generally more beneficial than conventional lettuce.

When selecting lamb's lettuce in the store, look for deep green, velvety leaves which are crisp. Wilted or discolored lamb's lettuce should be avoided. Some markets sell whole heads, in which case the leaves will form a rosette. Rinse lamb's lettuce before use, and try to use it within three to four days, because it is very delicate. Avoid crushing lamb's lettuce and other salad greens, because bruising can turn greens bitter.