Lactuca virosa grows as a biennial, leafy stalk stemming from a large brown taproot. It starts as a low rosette at first, but extends with age, typically measuring up to four feet in height. It is a wild relative of lactuca sativa, which contains the group of cultivars that are commonly used in salads. Virosa, one of several species known as wild lettuce, is sometimes used in salads too. But it is quite bitter and therefore less palatable. All wild lettuce species have this quality, but it has been bred out of lactuca sativa over hundreds of years of cultivation. More so than an edible, virosa was used by doctors as a medicinal, particularly a sedative. It is also called opium lettuce because the plant exudes a sticky, off-white latex when damaged. Used as tincture, drank in tea or eaten as dried latex balls, L. virosa was used to treat restlessness and insomnia, coughs, colic, hyperactivity and pain. Its effects are the result of lactucopicrin and lactucin. It is still sold by many herb shops today, although the quality seems to vary much. Fresh herb or freshly collected latex is probably more reliable.