Lactuca spp.

The genus Lactuca, commonly known as lettuce, is a genus of flowering plants in the daisy family, Asteraceae. The genus includes at least 50 species, distributed worldwide, but mainly in temperate Eurasia. Most lactuca species produce a milky latex, which is where 'Lactuca' is derived from, the Latin meaning 'having milky sap'. This milky sap contains sedative non-opiate alkaloids to varying degrees and it is very high in lactucin, which has a distinct sedative effect. Lactuca species are diverse and take a wide variety of forms. Its best-known representative is the common garden lettuce, L. sativa. While L. virosa is widely renowned in the medicinal ethnobotanical communities for its sedative effects and many species are common weeds.