Milky juice or latex.
Traditionally, lettuce opium has been employed for treating several medical conditions varying from assisting the circulatory system to treating enlarged/ distended genitals. In Europe, herbalists employ lettuce opium as a substitute for opium in cough mixtures. A tincture is prepared with the herb in homeopathy for treating infections of the respiratory tract, such as asthma, cough, laryngitis and bronchitis as well as infections of the urinary tract. The juice extracted from the stem covering the herb produces a therapeutic extract called thridace - the exploit as well as effectiveness of this substance is greatly in doubt. Preparations with lettuce have been used extensively in traditional Chinese medicine. The dried out juice extracted from the plant is an antiseptic and, hence, prescribed for external application to wounds. The seeds of the herb have been used in the form of galactogogue with a view to enhance the flow of breast milk in nursing mothers. Moreover, it has been maintained by some herbalists that the flowers as well as the seeds of the herb are helpful in lowering fevers. More lately, products of lettuce opium have been sold in the form of legal highs or as substitutes to narcotics with the intention to be smoked by itself or in conjugation with marijuana to augment effectiveness as well as taste of the herb. A physician based in Philadelphia, J. R. Coxe was the first to introduce lettuce opium to traditional American medicine way back in 1799. In effect, lettuce opium was widely used in the form of an analgesic and sedative for about a century after its introduction into traditional American medicine and subsequently the herb was no more preferred for this purpose. By the middle of the 20th century, lettuce opium gradually became insignificant. However, all of a sudden, lettuce opium was revived by the members of the American hippie movement during mid-1970s in the form of a legal psychotropic or a medication for altering the mind. A wide assortment of preparations using lettuce opium were advertised extensively in counter-culture publications, either in the form of an unadulterated substance or blended with potency enhancing herbs, for instance damiana or catnip. These products were meant to be smoked with a view to generate a sensation of ecstasy as well as happiness (precisely speaking, being on a 'high'). As years passed, a section of people have made recurring endeavours to demonstrate the tranquilizing as well as the analgesic (pain relieving) actions of lettuce opium as well as to discover the active principles that may perhaps be responsible for these effects of the herb.
The findings of an all-embracing pharmacological research involving lettuce opium, which were published in 1940, revealed that the freshly obtained milky juice enclosed two bitter principles - lactucopicrin and lactucin. It was found that these two substances had specific sedative or depressant actions on the central nervous system (CNS) in little animals. Nevertheless, it was also found that these two amalgams were somewhat volatile and the lactucarium that is available commercially possessed very little, if any, or no action.
There is no report of clinically significant adverse actions of smoking lettuce opium. Nevertheless, there exists a potential relation between ingestion of lettuce and a local oral allergic effect.