Wild Lettuce

What is Wild Lettuce?

Wild lettuce is a tall, bitter biennial of the daisy family, a wild relative of cultivated lettuce, native to Europe, North Africa and western Asia. When the stem or leaves are cut they exude a milky latex that dries into a brownish substance called lactucarium, or “lettuce opium” — the historical source of its sedative reputation. It is used as a tea, tincture or, less commonly, smoked.

Traditional & Modern Uses

Historically, lactucarium was used as a mild sedative and cough remedy, sometimes as a gentle substitute for opium (though it is chemically unrelated) — a use well documented in the 19th-century materia medica literature ^{22Reference 22Trojanowska A · 2005ReviewLettuce (Lactuca sp.) as a medicinal plant in Polish publications of the 19th century — historical reviewView study →}. Wild lettuce has a folk reputation for easing restlessness, mild pain and promoting sleep, and for calming irritable coughs. Contemporary herbal use continues along these lines as a gentle relaxant and sleep aid. It is worth keeping traditional reputation and tested activity distinct: the sedative and analgesic claims now have some preclinical mechanistic support, while the cough/expectorant use rests on tradition alone (see the research section below).

Phytochemistry

The defining constituents are the bitter sesquiterpene lactones of the dried latex (lactucarium): lactucin, lactucopicrin and lactucic acid, with lactucin-8-sulfate also present. In animal tests the isolated compounds lactucin and lactucopicrin — molecules shared with chicory and garden lettuce, so tested here as purified guaianolides rather than as a whole wild-lettuce preparation — showed sedative and analgesic activity, with lactucopicrin the most potent ^{1Reference 1Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivoView study →}. These guaianolides, not any opiate, account for the plant’s “lettuce opium” reputation. Lactuca virosa also yields pentacyclic triterpenes such as lupeol, taraxasterol and germanicol, and the sterol β-sitosterol. Despite the nickname it contains no opiate alkaloids.

Constituent Summary

Sesquiterpene-lactone content varies widely with plant age, part and the way the latex is collected and dried; published quantitative figures come mainly from latex of other Lactuca species rather than L. virosa itself, so amounts here are given as No Data. † marks the lactucarium bitters that characterise the herb.

Pharmacology & Research

Wild lettuce sits almost entirely in the preclinical evidence tier: there is a moderate body of laboratory and animal work on its characteristic bitter sesquiterpene lactones — chiefly lactucin and lactucopicrin — but no clinical trial has ever tested Lactuca virosa itself, and the herb has no registered trials of any kind. A crucial reading caveat runs through the whole literature: the two compounds that carry wild lettuce’s reputation are shared with chicory (Cichorium intybus) and garden lettuce (Lactuca sativa), and most mechanistic and in vivo data were generated in those species or on the isolated molecules, not on wild-lettuce preparations. The strongest and most consistent signal is sedative/sleep-supporting activity acting through GABA-A and adenosine pathways, replicated across several rodent studies, with the one study using L. virosa’s own guaianolides showing mouse analgesia comparable to ibuprofen ^{1Reference 1Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivoView study →}. Anti-inflammatory NF-κB suppression by lactucopicrin is the best-developed emerging mechanism, demonstrated in live mice ^{8,9Reference 8Weng H et al. · 2021AnimalNatural lactucopicrin alleviates importin-α3–mediated NF-κB activation in inflamed endothelial cells and improves sepsis in mice — animal in vivoView study →Reference 9He L et al. · 2021AnimalLactucopicrin inhibits cytoplasmic dynein–mediated NF-κB activation in inflamed macrophages and alleviates atherogenesis in ApoE-deficient mice — animal in vivoView study →}. Because sesquiterpene-lactone content varies enormously with plant age, part, and how the latex is dried, none of this translates cleanly to a standardised human dose.

0. Evidence by indication

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric, and I’ll keep honing the formula over time. Each indication name links down to its write-up.

Indication	Support	Rests on
Sedative & sleep-supporting	██████░░░░ 62%	Replicated rodent sleep studies via GABA-A/adenosine; human trials used L. sativa seed oil, not wild lettuce.
Anti-inflammatory	██████░░░░ 58%	Lactucopicrin NF-κB suppression in live mice (sepsis, atherosclerosis) — but isolated compound, mostly from chicory.
Analgesic	██████░░░░ 55%	One mouse study of L. virosa guaianolides at ibuprofen-comparable doses; strong traditional backing, no human data.
Cognitive / neuroprotective	████░░░░░░ 45%	In vitro acetylcholinesterase inhibition + neuritogenesis; no whole-organism or human data.
Anticancer	████░░░░░░ 40%	Glioblastoma cell line (L. virosa lactucopicrin) + one gastric-cancer mouse model; early-stage.
Antimalarial	███░░░░░░░ 30%	Single in vitro Plasmodium falciparum assay of isolated lactucin/lactucopicrin from chicory.

1. Sedative & sleep-supporting

This is the traditional core of wild lettuce and its best-mapped mechanism, though the direct evidence is preclinical. In mice, lactucin and lactucopicrin reduced spontaneous locomotor activity — a sedation readout — while a closely related guaianolide did not ^{1Reference 1Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivoView study →}. Rodent studies of lettuce extracts standardised for these same lactones consistently increase sleep duration and non-REM sleep and reverse caffeine-induced arousal, with effects blocked by the benzodiazepine-site antagonist flumazenil, pointing to a GABA-A/benzodiazepine mechanism; lactucin and lactucopicrin bind the GABA-A–benzodiazepine receptor with 81% and 56% affinity respectively ^{2,5Reference 2Kim HW et al. · 2019AnimalEffectiveness of the sleep enhancement by green romaine lettuce (Lactuca sativa) in a rodent model — animal in vivoView study →Reference 5Kim HD et al. · 2017AnimalSleep-inducing effect of lettuce (Lactuca sativa) varieties on pentobarbital-induced sleep — animal in vivoView study →}. A separate mouse study attributes lettuce’s sleep effect to up-regulation of the adenosine A1 receptor alongside GABA-A subunits ^{4Reference 4Lee M et al. · 2024AnimalLactuca sativa extract enhances sleep duration through upregulation of adenosine A1 receptor and GABA-A receptor subunits in pentobarbital-injected mice — animal in vivoView study →}, and a GABA-A route was confirmed by EEG in another ^{3Reference 3Ahn Y et al. · 2023AnimalHeukharang lettuce (Lactuca sativa) leaf extract displays sleep-promoting effects through GABA-A receptor — animal in vivoView study →}. Two small human trials report sedative/hypnotic benefit — but both used Lactuca sativa (garden lettuce) seed oil, not wild lettuce, so they support the mechanism rather than the herb ^{6,7Reference 6Yakoot M et al. · 2011RCTPilot study of the efficacy and safety of lettuce seed oil in patients with sleep disorders — randomised placebo-controlled trialView study →Reference 7Taherzadeh Z et al. · 2020RCTEvaluation of sedative effects of an intranasal dosage form containing saffron, lettuce seeds and sweet violet in primary chronic insomnia — randomised, double-blind, placebo-controlled trialView study →}.

Gap: No trial has ever tested L. virosa itself; the human data are from a different species and preparation (garden-lettuce seed oil), and there is no standardised lactucarium dose.

2. Anti-inflammatory

The most active emerging area, driven almost entirely by lactucopicrin. In lipopolysaccharide- or TNF-α–stimulated macrophages and endothelial cells it dose-dependently suppresses NF-κB activation — not by touching the IKK complex or p65 DNA binding, but by destabilising importin-α3 mRNA and blocking dynein-mediated p65 nuclear transport ^{8,9,10Reference 8Weng H et al. · 2021AnimalNatural lactucopicrin alleviates importin-α3–mediated NF-κB activation in inflamed endothelial cells and improves sepsis in mice — animal in vivoView study →Reference 9He L et al. · 2021AnimalLactucopicrin inhibits cytoplasmic dynein–mediated NF-κB activation in inflamed macrophages and alleviates atherogenesis in ApoE-deficient mice — animal in vivoView study →Reference 10Ávila-Gálvez MÁ et al. · 2025In vitroLactucopicrin: a sesquiterpene lactone with anti-inflammatory activity modulating the crosstalk between NF-κB and AHR pathways — in vitroView study →}. These are not cell-only findings: oral lactucopicrin cut mortality by ~30% in LPS-induced septic mice and reduced plaque burden in atherosclerotic ApoE-deficient mice ^{8,9Reference 8Weng H et al. · 2021AnimalNatural lactucopicrin alleviates importin-α3–mediated NF-κB activation in inflamed endothelial cells and improves sepsis in mice — animal in vivoView study →Reference 9He L et al. · 2021AnimalLactucopicrin inhibits cytoplasmic dynein–mediated NF-κB activation in inflamed macrophages and alleviates atherogenesis in ApoE-deficient mice — animal in vivoView study →}. Related guaianolides including lactucin show strong anti-neuroinflammatory activity in cultured cells (IC50 ≈ 1.8 µM) ^{12Reference 12Wei Z et al. · 2024In vitroGuaianolide sesquiterpene lactones from Cichorium glandulosum and their anti-neuroinflammation activities (including lactucin) — in vitroView study →}, and lactucopicrin also curbs macrophage foam-cell formation by lowering LOX-1 ^{11Reference 11Li Q et al. · 2022In vitroTerpene lactucopicrin limits macrophage foam cell formation by reducing LOX-1 in lipid rafts — in vitroView study →}.

Gap: Every result is on the isolated compound — largely sourced from chicory — at doses far above what a wild-lettuce tea or tincture would deliver; no study has shown a whole-herb L. virosa preparation is anti-inflammatory in vivo.

3. Analgesic

Wild lettuce’s folk reputation for easing mild pain has one direct experimental anchor. In mice, lactucin, lactucopicrin and 11β,13-dihydrolactucin — described as characteristic lactones of L. virosa and chicory — produced analgesia in the hot-plate and tail-flick tests at 15–30 mg/kg, comparable to ibuprofen at 30–60 mg/kg, with lactucopicrin the most potent ^{1Reference 1Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivoView study →}. This is peripheral/central antinociception from the herb’s own guaianolides, and it is chemically unrelated to opioids despite the “lettuce opium” nickname — the plant contains no opiate alkaloids. Beyond this single study the analgesic literature is traditional rather than experimental.

Gap: Rests essentially on one mouse study of isolated compounds; there is no dose-response work, no human analgesia data, and no demonstration that a drunk tea or tincture reaches analgesic exposure.

4. Cognitive / neuroprotective

An in-vitro-only signal built on acetylcholinesterase (AChE) inhibition — the same enzyme target as several Alzheimer’s drugs. Activity-guided fractionation of chicory identified lactucopicrin and 8-deoxylactucin as dose-dependent AChE inhibitors (IC50 ≈ 150 and 308 µM) ^{13Reference 13Rollinger JM et al. · 2005In vitroApplication of the in-combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybus (8-deoxylactucin, lactucopicrin) — in vitroView study →}, and calorimetry plus docking confirmed lactucopicrin as the stronger binder among the sesquiterpene lactones ^{14Reference 14Jaśkiewicz A et al. · 2022In vitroEvaluation of activity of sesquiterpene lactones and chicory extracts as acetylcholinesterase inhibitors in calorimetric and docking simulation studies — in vitroView study →}. In cultured neuronal cells lactucopicrin also promotes neurite outgrowth and raises NGF, BDNF and NT-3 via Ca²⁺/CaMKII/ATF1 signalling ^{15Reference 15Venkatesan R et al. · 2017In vitroLactucopicrin potentiates neuritogenesis and neurotrophic effects by regulating Ca²⁺/CaMKII/ATF1 signaling — in vitroView study →}.

Gap: The inhibitory concentrations are high (micromolar) and everything is cell-based — no animal cognition model, no blood-brain-barrier or bioavailability data, and no link to wild-lettuce dosing.

5. Anticancer

Early-stage and heterogeneous. Lactucopicrin isolated from L. virosa was cytotoxic to U87Mg glioblastoma cells, triggering autophagy, G2/M arrest (via p53/p21) and apoptosis, with the effect reversed by the antioxidant N-acetylcysteine — implicating reactive oxygen species ^{16Reference 16Rotondo R et al. · 2020In vitroImplication of lactucopicrin in autophagy, cell-cycle arrest and oxidative stress to inhibit U87Mg glioblastoma cell growth — in vitroView study →}. Separately, lactucin suppressed gastric-cancer cell growth and induced apoptosis through MAPK signalling, with confirmation in a mouse xenograft ^{17Reference 17Wei D et al. · 2026AnimalLactucin inhibits growth and induces apoptosis in gastric cancer cells by targeting MAPK signaling — animal in vivo (xenograft)View study →}.

Gap: Single cell lines per cancer type, isolated compounds only, and no evidence a wild-lettuce preparation reaches cytotoxic concentrations in vivo — this is exploratory pharmacology, not an established use.

6. Antimalarial

The weakest scored signal. Screening of chicory constituents against Plasmodium falciparum found the shared guaianolides lactucin and lactucopicrin to be the active antimalarial molecules in vitro ^{18Reference 18Bischoff TA et al. · 2004In vitroAntimalarial activity of lactucin and lactucopicrin: sesquiterpene lactones isolated from Cichorium intybus — in vitroView study →}. The compounds are light-sensitive, which complicates any therapeutic reading.

Gap: A single in vitro assay of isolated compounds sourced from chicory, with no animal model, no potency benchmarking against antimalarial standards, and no relevance to how wild lettuce is actually used.

Mechanisms

Mechanism	Drives	Key compounds
GABA-A / benzodiazepine-site binding; adenosine A1 up-regulation	sedative & sleep-supporting	lactucin, lactucopicrin
NF-κB ↓ (importin-α3 destabilisation, dynein-mediated p65 transport block)	anti-inflammatory	lactucopicrin
Guaianolide antinociception (non-opioid)	analgesic	lactucin, lactucopicrin
Acetylcholinesterase inhibition; NGF/BDNF/CaMKII signalling	cognitive / neuroprotective	lactucopicrin, 8-deoxylactucin
ROS induction, G2/M arrest, MAPK-linked apoptosis	anticancer	lactucopicrin, lactucin

Clinical trials

No registered clinical trials of Lactuca virosa or its constituents were identified — the evidence base is preclinical, and the only human sedation data come from separate small trials of Lactuca sativa (garden lettuce) seed oil.

Completed	Planned	Terminated	Preclinical
0	0	0	~20

Last checked: July 2026.

Dosage

In research, wild lettuce has never been given as a standardised whole-herb dose — every reported dose is either an isolated guaianolide in mice or a different Lactuca species/preparation, so none is a wild-lettuce dose you can act on.

Indication	Preparation	Dose	Est. dried-herb equivalent	Source
Analgesia / sedation	Isolated lactucin/lactucopicrin, oral, mice	15–30 mg/kg	— (isolated compound, not whole herb)	1Reference 1Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivoView study →
Sleep support	L. sativa leaf/seed extract, oral, rodents	100–150 mg/kg extract	— (different species; extract not standardised to herb weight)	2,3Reference 2Kim HW et al. · 2019AnimalEffectiveness of the sleep enhancement by green romaine lettuce (Lactuca sativa) in a rodent model — animal in vivoView study →Reference 3Ahn Y et al. · 2023AnimalHeukharang lettuce (Lactuca sativa) leaf extract displays sleep-promoting effects through GABA-A receptor — animal in vivoView study →
Insomnia (human)	L. sativa seed oil capsule	1000 mg/day	— (garden-lettuce seed oil, not wild lettuce)	6Reference 6Yakoot M et al. · 2011RCTPilot study of the efficacy and safety of lettuce seed oil in patients with sleep disorders — randomised placebo-controlled trialView study →

The dried-herb-equivalent column is left blank throughout: every reported dose is either an isolated compound (mg/kg in mice) or a different species/preparation, and no marker-% for L. virosa lactucarium is available, so any back-conversion would be invented. These are research figures, not recommendations.

Traditional Dosage

Western herbal practice uses the dried leaf as a tea or the concentrated lactucarium sparingly. No WHO/ESCOP/EMA-HMPC or Commission E monograph establishes a validated L. virosa dose, so the figures below are traditional guides only, not clinical doses.

System	Preparation	Dose
Western herbal	Dried leaf, infusion	~1–2 g as a tea, once to a few times daily (traditional)
Western herbal	Tincture / lactucarium (dried latex)	Dosed sparingly — lactucarium is far more concentrated than leaf; low drop-dose range traditionally

Traditional and research doses are not interchangeable, and the traditional figures above are unverified against a primary pharmacopoeial source.

Safety

Wild lettuce is generally mild in traditional doses, but it is genuinely sedating, so it should not be combined with alcohol, benzodiazepines, opioids, or other CNS depressants, and should not be taken before driving or operating machinery. Documented overdose is real, not theoretical: a case series of eight patients who ate wild lettuce described toxicity requiring hospital care — including one 48-hour intensive-care admission — with agitation, and all recovered on supportive treatment ^{19Reference 19Besharat S et al. · 2009Case reportWild lettuce (Lactuca virosa) toxicity — case seriesView study →}, and a separate case documents abuse of the plant for its psychoactive effect ^{20,21Reference 20Spadari M et al. · 2003Case reportAbuse of Lactuca virosa — case reportView study →Reference 21Lo Faro AF et al. · 2020ReviewBiomedical analysis of new psychoactive substances of natural origin — reviewView study →}. Despite the “opium lettuce” nickname the plant contains no opiate alkaloids; its activity comes from bitter sesquiterpene lactones (lactucin, lactucopicrin), which are potential contact allergens within the Asteraceae/daisy family. Smoking any plant material, including dried latex, carries respiratory risk.

Scope note: no formal pharmacokinetic or CYP450 interaction study exists — the CNS-depressant caution is pharmacodynamic (additive sedation) and mechanistic, not from a trial. Absence of an interaction report is not evidence of safety.

Pregnancy & lactation

Not established — avoid. Safety of wild lettuce in pregnancy and lactation has not been formally studied, and given its sedative activity and the absence of any reproductive-toxicity data it is best avoided during pregnancy and breastfeeding. This is a precaution from lack of data, not evidence of harm.

Scope note: pregnancy and lactation were not specifically researched in this package — the verdict is precautionary.

References

1. Wesołowska A, et al. (2006). Analgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice — animal in vivo. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/16621374/
2. Kim HW, et al. (2019). Effectiveness of the sleep enhancement by green romaine lettuce (Lactuca sativa) in a rodent model — animal in vivo. Biological & Pharmaceutical Bulletin. https://pubmed.ncbi.nlm.nih.gov/31582660/
3. Ahn Y, et al. (2023). Heukharang lettuce (Lactuca sativa) leaf extract displays sleep-promoting effects through GABA-A receptor — animal in vivo. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/37149068/
4. Lee M, et al. (2024). Lactuca sativa extract enhances sleep duration through upregulation of adenosine A1 receptor and GABA-A receptor subunits in pentobarbital-injected mice — animal in vivo. Journal of Medicinal Food. https://pubmed.ncbi.nlm.nih.gov/38603571/
5. Kim HD, et al. (2017). Sleep-inducing effect of lettuce (Lactuca sativa) varieties on pentobarbital-induced sleep — animal in vivo. Food Science and Biotechnology. https://pubmed.ncbi.nlm.nih.gov/30263607/
6. Yakoot M, et al. (2011). Pilot study of the efficacy and safety of lettuce seed oil in patients with sleep disorders — randomised placebo-controlled trial. International Journal of General Medicine. https://pubmed.ncbi.nlm.nih.gov/21731897/
7. Taherzadeh Z, et al. (2020). Evaluation of sedative effects of an intranasal dosage form containing saffron, lettuce seeds and sweet violet in primary chronic insomnia — randomised, double-blind, placebo-controlled trial. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/32736046/
8. Weng H, et al. (2021). Natural lactucopicrin alleviates importin-α3–mediated NF-κB activation in inflamed endothelial cells and improves sepsis in mice — animal in vivo. Biochemical Pharmacology. https://pubmed.ncbi.nlm.nih.gov/33684389/
9. He L, et al. (2021). Lactucopicrin inhibits cytoplasmic dynein–mediated NF-κB activation in inflamed macrophages and alleviates atherogenesis in ApoE-deficient mice — animal in vivo. Molecular Nutrition & Food Research. https://pubmed.ncbi.nlm.nih.gov/33377310/
10. Ávila-Gálvez MÁ, et al. (2025). Lactucopicrin: a sesquiterpene lactone with anti-inflammatory activity modulating the crosstalk between NF-κB and AHR pathways — in vitro. Journal of Medicinal Chemistry. https://pubmed.ncbi.nlm.nih.gov/41186284/
11. Li Q, et al. (2022). Terpene lactucopicrin limits macrophage foam cell formation by reducing LOX-1 in lipid rafts — in vitro. Molecular Nutrition & Food Research. https://pubmed.ncbi.nlm.nih.gov/34932892/
12. Wei Z, et al. (2024). Guaianolide sesquiterpene lactones from Cichorium glandulosum and their anti-neuroinflammation activities (including lactucin) — in vitro. Phytochemistry. https://pubmed.ncbi.nlm.nih.gov/39032793/
13. Rollinger JM, et al. (2005). Application of the in-combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybus (8-deoxylactucin, lactucopicrin) — in vitro. Current Drug Discovery Technologies. https://pubmed.ncbi.nlm.nih.gov/16472227/
14. Jaśkiewicz A, et al. (2022). Evaluation of activity of sesquiterpene lactones and chicory extracts as acetylcholinesterase inhibitors in calorimetric and docking simulation studies — in vitro. Nutrients. https://pubmed.ncbi.nlm.nih.gov/36079888/
15. Venkatesan R, et al. (2017). Lactucopicrin potentiates neuritogenesis and neurotrophic effects by regulating Ca²⁺/CaMKII/ATF1 signaling — in vitro. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/28011163/
16. Rotondo R, et al. (2020). Implication of lactucopicrin in autophagy, cell-cycle arrest and oxidative stress to inhibit U87Mg glioblastoma cell growth — in vitro. Molecules. https://pubmed.ncbi.nlm.nih.gov/33322048/
17. Wei D, et al. (2026). Lactucin inhibits growth and induces apoptosis in gastric cancer cells by targeting MAPK signaling — animal in vivo (xenograft). Folia Histochemica et Cytobiologica. https://pubmed.ncbi.nlm.nih.gov/42138553/
18. Bischoff TA, et al. (2004). Antimalarial activity of lactucin and lactucopicrin: sesquiterpene lactones isolated from Cichorium intybus — in vitro. Journal of Ethnopharmacology. https://pubmed.ncbi.nlm.nih.gov/15507374/
19. Besharat S, et al. (2009). Wild lettuce (Lactuca virosa) toxicity — case series. BMJ Case Reports. https://pubmed.ncbi.nlm.nih.gov/21686920/
20. Spadari M, et al. (2003). Abuse of Lactuca virosa — case report. Presse Médicale. https://pubmed.ncbi.nlm.nih.gov/12762295/
21. Lo Faro AF, et al. (2020). Biomedical analysis of new psychoactive substances of natural origin — review. Journal of Pharmaceutical and Biomedical Analysis. https://pubmed.ncbi.nlm.nih.gov/31704129/
22. Trojanowska A (2005). Lettuce (Lactuca sp.) as a medicinal plant in Polish publications of the 19th century — historical review. Kwartalnik Historii Nauki i Techniki. https://pubmed.ncbi.nlm.nih.gov/17153150/