Lactuca virosa is a plant in the Lactuca (lettuce) genus, ingested often for its mild psychotropic (specifically hypnotic or sedative) effects which are often described as being similar to that of opium. It is related to common lettuce (L. sativa), and is often called Wild Lettuce, Bitter lettuce, Laitue vireuse, Opium Lettuce, Poisonous Lettuce, or Rakutu-Karyumu-So. It can be found locally in the south east and east of England. In the rest of Great Britain it is very rare, and in Ireland it is absent.