Lettuce Opium

Scientific Name(s): Lactuca sativa var capitata L. (garden lettuce)., Lactuca virosa L. (wild lettuce).
Common Name(s): Acrid lettuce, Garden lettuce, German lactucarium, Greater prickly lettuce, Green endive, Lettuce opium, Strong-scented lettuce, Wild lettuce

Medically reviewed by Drugs.com. Last updated on Nov 8, 2023.

Clinical Overview

Use

Lettuce opium has been used as a topical antiseptic, as a folk medicine to ameliorate a variety of conditions, and as a narcotic substitute or enhancer. It is also a mild sedative and hypnotic. With the recent exception of a small study on insomnia in pregnant women, there is little clinical evidence to support its use for other indications.

Dosing

There is limited clinical evidence to support specific dose recommendations. Doses of 1,000 mg of lettuce seed have been used for periods of up to 2 weeks in 1 small double-blind randomized placebo-controlled trial.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is under investigation.

Interactions

None well documented.

Adverse Reactions

Lettuce opium contains sesquiterpene lactones; therefore, oral ingestion may be associated with allergic reactions.

Toxicology

Reports of mydriasis, dizziness, anxiety, urinary retention, decreased bowel sounds, and sympathetic over-activity have been published.

Scientific Family

• Asteraceae (daisy)

Botany

Widely cultivated, lettuce flowers from July to September. This biennial herb grows to 1.8 m. The large leaves can attain lengths of 0.46 m. The stalks are rich in a milky-white sap that flows freely when the stems are broken.USDA 2016

History

Lettuce opium has been used in folk medicine for indications ranging from aiding circulation to treating swollen genitals. In Europe, it is used as a substitute for opium in cough mixtures.(Lewis 1977) In homeopathy, a tincture has been used for laryngitis, bronchitis, asthma, coughing, and urinary tract infections.(Schauenberg 1977) The juice of the stem covering yields a medicinal extract known as thridace, the use and efficacy of which is widely disputed.(Grieve 1971)

In Chinese medicine, lettuce preparations have been widely used. The dried juice has been recommended as a topical wound antiseptic, and the seeds have been used as a galactogogue (to increase the flow of milk in nursing mothers). It has been claimed that the flowers and seeds are effective in reducing fevers.(Brown 1977) Lettuce opium products have been marketed as legal highs or narcotic substitutes intended to be smoked alone or in combination with marijuana to enhance potency and flavor.(Huang 1982)

Chemistry

Some confusion exists regarding the nomenclature of the products derived from L. virosa and related plants. Flowering lettuce plants contain large amounts of a milky-white sap, which has a bitter taste and strong opiate-like odor. When the juice is collected and is exposed to air, it turns a brownish color. This substance is called lactucarium, a mixture of compounds to which the touted narcotic properties of the product have been ascribed. The main active compounds isolated from lactucarium are lactucine (LC) and lactucopicrin (LCP), 2 guaian-type sesquiterpene lactones.(Lo Faro 2020) Several other molecules of the same chemical class have been also identified such as 8-deoxylactucin (8-deO-LC) and derivatives.(Lo Faro 2020) Additionally, the mixture contains a volatile oil, caoutchouc, mannitol, and lactucerol (taraxasterol). Lactucerin, also found in the latex, is the acetyl derivative of taraxasterol, a widely distributed triterpene.(Bachelor 1973, Brown 1977)

Reports that lactucarium contains hyoscyamine have been refuted.(Willaman 1970) A report that L. virosa contains N-methyl-beta-phenylethylamine(Marquardt 1976) also has been refuted.(Huang 1982)

Uses and Pharmacology

Hallucinogenic effects

A variety of legal, alternate "hallucinogenic" products containing lettuce opium have been available on the market. Brand names of such products include Lettucine, Black Gold, Lettucene, Lettuce Hash, and Lopium. These products contain a lettuce derivative or lactucarium and are smoked in pipes or heated in small bowls, and the vapors are inhaled. These extracts are sometimes combined with damiana distillates, African yohimbe bark, or catnip distillates.

Clinical data

The hallucinogenic effect is usually mild and appears to be related to the degree of user expectation. There is no pharmacologic basis for the purported hallucinogenic effects of lettuce opium.

Insomnia in pregnancy

Clinical data

A double-blind, randomized, placebo-controlled trial on efficacy and safety of Lactuca sativa L. seeds on pregnancy-related insomnia demonstrated that lettuce seed decreased insomnia during pregnancy and could be recommended as a safe natural remedy for treatment of pregnancy-related insomnia. In a prospective randomized clinical trial (N=100), pregnant women with insomnia 20 to 45 years of age received capsules containing 1,000 mg of lettuce seed or a placebo daily for 2 weeks.(Pour 2018) The main outcome was the quality of sleep, which was measured using the Pittsburgh Sleep Quality Index (PSQI). An improvement in the PSQI score was significantly greater in patients receiving lettuce seed than those receiving the placebo (n=50). Linear regression analysis showed that, after controlling for the other variables, the average sleep score of the experimental group was significantly lower than for the placebo group (P=0.03).(Pour 2018)

Other uses

Lettuce leaf cigarettes have been marketed as nicotine-free tobacco substitutes. Support for such alternatives has been variable because of slow acceptance of the unique flavor and the lack of a nicotine-induced kick.

Phytochemical and biological screening of several Lactuca species indicates that the genus has no antimicrobial activity, slight antitumor activity, and can produce CNS effects in mice.(Bhakuni 1971, Fong 1972) However, the Lactuca species have resistance to various viruses, bacteria, and fungi (Bremia lactucae).(Chupeau 1994)

While lactucin and lactucopicrin have been reported to have depressant and sedative activity on the CNS, these compounds are chemically unstable; commercial lactucarium contains little of these unstable compounds.(Tyler 1987) the latex of L. sativa has been shown to inhibit the growth of Candida albicans in vitro.(Moulin-Traffort 1990) Extracts of L. sativa resulted in hypotension when administered to dogs.(Huang 1982)

Dosing

Doses of 1,000 mg of lettuce seed have been used successfully for periods of up to 2 weeks to treat insomnia in pregnant women.(Pour 2018)

Pregnancy / Lactation

Information regarding safety and efficacy in pregnancy and lactation is under investigation.

Interactions

None well documented.

Adverse Reactions

Case reports are lacking; however, a possible association exists between lettuce ingestion and a localized oral allergic reaction.(Bernton 1974) A subjective-self reported study showed that lettuce seed could be used as a safe hypnotic treatment for pregnant women with no side effects; this seems to be attributable to lettuce seed given at a particular dose.(Pour 2018)

Toxicology

Reports of mydriasis, dizziness, anxiety, urinary retention, decreased bowel sounds, and sympathetic over-activity have been published. An anticholinergic mechanism has been suggested.(Mullins 1998) Mortality in dogs has been reported following intravenous administration.(Besharat 2009, Mullins 1998)

Injection of wild lettuce opium and valerian root have been associated with transient fevers, chills, abdominal pain, flank and back pain, neck stiffness, headache, leucocytosis, and mild liver function abnormalities in 3 young adults.(Lo Faro 2020)

References

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This information relates to an herbal, vitamin, mineral or other dietary supplement. This product has not been reviewed by the FDA to determine whether it is safe or effective and is not subject to the quality standards and safety information collection standards that are applicable to most prescription drugs. This information should not be used to decide whether or not to take this product. This information does not endorse this product as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this product. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this product. This information is not specific medical advice and does not replace information you receive from your health care provider. You should talk with your health care provider for complete information about the risks and benefits of using this product.

This product may adversely interact with certain health and medical conditions, other prescription and over-the-counter drugs, foods, or other dietary supplements. This product may be unsafe when used before surgery or other medical procedures. It is important to fully inform your doctor about the herbal, vitamins, mineral or any other supplements you are taking before any kind of surgery or medical procedure. With the exception of certain products that are generally recognized as safe in normal quantities, including use of folic acid and prenatal vitamins during pregnancy, this product has not been sufficiently studied to determine whether it is safe to use during pregnancy or nursing or by persons younger than 2 years of age.

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