Plant Profile

Wild Lettuce

Lactuca virosa
Family: Asteraceae  ·  Parts used: Aerial parts and dried latex (lactucarium)  ·  Also known as: Bitter lettuce, Opium lettuce, Lactucarium

The complete database record: 2 documented constituents, 4 pharmacological actions, 8 traditional / indicated uses, with 15 cited sources.

Botanical Description

Tall, bristly biennial herb with a milky latex throughout, and prickly-edged, often blue-green leaves that tend to twist to align edge-on with the sun ('compass plant' habit). Small, pale yellow, dandelion-like flower heads are borne in loose branched clusters atop a tall, spiny-stemmed flowering stalk.[11]

Height: 1-2 m
Habit: Tall, bristly biennial herb; low rosette in year one, tall flowering stem in year two
Leaves: Prickly-edged, often blue-green, sometimes twisting edge-on to the sun
Flowers: Small, pale yellow, dandelion-like flower heads in loose branched clusters
Stem: Tall, spiny, exuding milky white latex when cut
Root: Taproot
Fruit: Small achene with a feathery pappus
Flowering Period: July-September (second year)

Habitat & Distribution

Grows on dry waste ground, roadsides, hedgerows and disturbed soil; native to Europe, North Africa and Western Asia and naturalised in North America.

Harvesting

The milky latex is traditionally collected by scoring the flowering stem and letting the exuded sap dry into lactucarium; the aerial parts (leaf and stem) are also cut and dried while the plant is flowering.[11]

Parts: Aerial parts and dried latex (lactucarium)
Season: Flowering (second year); latex collected by scoring the stem

Key Constituents

Sesquiterpene lactones (lactucin, lactucopicrin)[4, 11, 12]

Bitter, centrally-active constituents responsible for the sedative and pain-relieving effects; isolated lactucin and lactucopicrin produced analgesia comparable to ibuprofen and sedation in rodent tests.

Sesquiterpene lactonesSesquiterpenes
Lactucarium (the dried milky latex)[11]

The historical medicinal preparation, concentrating the active lactones.

Pharmacological Actions

Analgesic (pain relief)[4, 6, 11, 12]

Mild analgesic / anodyne for pain (lactucin and lactucopicrin act on the central nervous system) - in mice these compounds produced analgesia comparable to ibuprofen

Antitussive (cough suppressant)[5, 11]

Antitussive for an irritable, dry cough (traditional)

Anxiolytic / calming[11]

Calming for nervous tension and restlessness

Sedative / sleep support[4, 6, 7, 8, 11]

Sedative for sleeplessness / insomnia - lactucin and lactucopicrin showed sedative activity in animal models

Traditional & Indicated Uses

Anxiety[11]Preliminary · 1/10

inferred from anxiolytic action

Evidence: 1
Label: Anxiety

more plants for anxiety →detailed sources →

Back pain[4, 11, 12]Preliminary · 2/10

inferred from analgesic action

Evidence: 2
Label: Back pain

more plants for back pain →detailed sources →

Cough[11]Preliminary · 1/10

Antitussive for an irritable, dry cough (traditional)

Evidence: 1
Label: Cough

more plants for cough →detailed sources →

Headache[4, 11, 12]Preliminary · 2/10

inferred from analgesic action

Evidence: 2
Label: Headache

more plants for headache →detailed sources →

Insomnia / sleeplessness[4, 11]Preliminary · 2/10

Sedative for sleeplessness / insomnia - lactucin and lactucopicrin showed sedative activity in animal models

Mechanistic Exclude Ids: REF-2061, REF-2062
Evidence: 2
Label: Insomnia / sleeplessness

more plants for insomnia / sleeplessness →detailed sources →

Nervous tension[11]Preliminary · 1/10

Calming for nervous tension and restlessness

Evidence: 1
Label: Nervous tension

more plants for nervous tension →detailed sources →

Pain (general)[4, 11, 12]Preliminary · 2/10

Mild analgesic / anodyne for pain (lactucin and lactucopicrin act on the central nervous system) - in mice these compounds produced analgesia comparable to ibuprofen

Evidence: 2
Label: Pain (general)

more plants for pain (general) →detailed sources →

Stress[11]Preliminary · 1/10

inferred from anxiolytic action

Evidence: 1
Label: Stress

more plants for stress →detailed sources →

Traditional Use & History

Wild lettuce has a long folk history, reflected in the name 'opium lettuce', as a mild sedative and analgesic remedy for insomnia, nervous tension and pain, and as an antitussive for irritable dry cough, its dried latex (lactucarium) once used as a milder, non-addictive alternative to opium.[11]

Preparations

Infusion[11]

Dried aerial parts infused in hot water as a traditional calming, sleep-supporting tea.

Lactucarium (historical)[12]

Dried milky latex, the classic historical preparation, used cautiously given its overdose toxicity.

Dosage

Infusion[12]

Because of documented overdose toxicity (rapid heartbeat, heavy sedation, breathing difficulty), only conservative traditional herbal doses should be used and this herb should not be self-dosed at concentrated or extract strength without professional guidance. Educational reference only, not a prescription.

Safety, Cautions & Contraindications

Safety note[12]Info

Can be unsafe in large amounts or if harvested too early: overdose can cause sweating, fast heartbeat, dilated pupils, dizziness, ringing in the ears, vision changes, heavy sedation, breathing difficulty and, in extreme cases, death.

Safety note[11, 12]Caution

Its sedative effect can add to that of sedatives and alcohol - avoid combining and do not use before driving. As a daisy-family (Asteraceae) plant it can cause allergy; avoid in pregnancy and breastfeeding.

Herb-Drug Interactions

Sedatives Cns Depressants[14, 15]Caution
Mechanism: Wild lettuce is traditionally used as a calming, sedative herb; taken with sedatives, sleeping tablets or other central-nervous-system depressants (including alcohol) it may add to drowsiness and slowed reactions.
Reviewed By: Omnia Sana (owner-authorized)
Reviewed Date: 2026-07-03

Harvest Readiness

[13]

Part: aerial-parts
Signals: Cut the aerial parts (and collect the milky latex, lactucarium) as the plant comes into flower in summer, when the constituent peaks.
Basis: constituent
Constituent Note: Lactucarium (the sedative latex) is low in young plants and most concentrated when the plant comes into flower.
Source Quote: Concentrations of lactucarium are low in young plants and most concentrated when the plant comes into flower.
Species Confirmed: 1
Notes: PFAF (REF-3279); the readiness rests on the constituent peak - lactucarium is most concentrated as the plant comes into flower (in flower July-September). basis:constituent (the sourced statement is the constituent peak; no separate traditional-collection source, so not basis:both). Single lineage -> provisional.

External Identifiers

References & Sources

  1. Ullah, M.I., Anwar, R., Kamran, S., Gul, B. et al (2022) 'Evaluation of the Anxiolytic and Anti-Epileptogenic Potential of Lactuca serriola Seed Using Pentylenetetrazol-Induced Kindling in Mice and Metabolic Profiling of Its Bioactive Extract', Antioxidants (Basel), 11(11), pp. 2232. doi:10.3390/antiox11112232 Preclinical
    https://doi.org/10.3390/antiox11112232
  2. Lee, M., Park, J., Cho, W., Jun, Y. et al (2024) 'Lactuca L. Extract Enhances Sleep Duration Through Upregulation of Adenosine A1 Receptor and GABA-A Receptor Subunits in Pentobarbital-Injected Mice', Journal of Medicinal Food, 27(7), pp. 661-668. doi:10.1089/jmf.2023.K.0250 Preclinical
    https://doi.org/10.1089/jmf.2023.K.0250
  3. Paulsen, E. and Andersen, K.E (2015) 'Lettuce contact allergy', Contact Dermatitis, 74(2), pp. 67-75. doi:10.1111/cod.12458 Traditional / reference
    https://doi.org/10.1111/cod.12458
  4. Wesolowska, A., Nikiforuk, A., Michalska, K., Kisiel, W. and Chojnacka-Wojcik, E (2006) 'Analgesic and sedative activities of lactucin and some lactucin-like guaianolides in mice', Journal of Ethnopharmacology, 107(2), pp. 254--258. doi:10.1016/j.jep.2006.03.003 Preclinical
    https://doi.org/10.1016/j.jep.2006.03.003
  5. Gumprecht, T (1815) 'On the use of the Lactuca Virosa, in Hooping-Cough', Medico-Chirurgical Transactions, 6, pp. 608-617. doi:10.1177/095952871500600125 Traditional / reference
    https://doi.org/10.1177/095952871500600125
  6. Trojanowska, A (2005) 'Lettuce, Lactuca sp., as a medicinal plant in Polish publications of the 19th century', Kwartalnik Historii Nauki i Techniki, 50(3-4), pp. 123-134. Traditional / reference
    https://scholar.google.com/scholar?q=Lettuce%2C%20Lactuca%20sp.%2C%20as%20a%20medicinal%20plant%20in%20Polish%20publications%20of%20the%2019th%20century
  7. Spadari, M., Pommier, P., Canioni, D., Arditti, J., David, J.M. and Valli, M (2003) 'Abuse of Lactuca virosa', Presse Medicale, 32(15), pp. 702-703. Preclinical
    https://scholar.google.com/scholar?q=Abuse%20of%20Lactuca%20virosa
  8. Lo Faro, A.F., Di Trana, A., La Maida, N., Tagliabracci, A., Giorgetti, R. and Busardo, F.P (2019) 'Biomedical analysis of New Psychoactive Substances (NPS) of natural origin', Journal of Pharmaceutical and Biomedical Analysis, 179, pp. 112945. doi:10.1016/j.jpba.2019.112945 Meta-analysis / review
    https://doi.org/10.1016/j.jpba.2019.112945
  9. Besharat, S., Besharat, M. and Jabbari, A (2009) 'Wild lettuce (Lactuca virosa) toxicity', BMJ Case Reports, 2009, pp. bcr0620080134. doi:10.1136/bcr.06.2008.0134 Preclinical
    https://doi.org/10.1136/bcr.06.2008.0134
  10. Stojakowska, A., Malarz, J. and Kisiel, W (1994) 'Sesquiterpene Lactones in Tissue Culture of Lactuca virosa', Planta Medica, 60(1), pp. 93-94. doi:10.1055/s-2006-959419 Preclinical
    https://doi.org/10.1055/s-2006-959419
  11. Herbal Reality (n.d.) 'Wild Lettuce (Lactuca virosa): Benefits, Uses, Safety'. Available at: https://www.herbalreality.com/herb/wild-lettuce/ Traditional / reference
    https://www.herbalreality.com/herb/wild-lettuce/
  12. RxList (n.d.) 'Wild Lettuce: Health Benefits, Side Effects, Uses, Dose & Precautions'. Available at: https://www.rxlist.com/supplements/wild_lettuce.htm Traditional / reference
    https://www.rxlist.com/supplements/wild_lettuce.htm
  13. Plants For A Future 'Lactuca virosa (Great Lettuce, Bitter Lettuce)'. Available at: https://pfaf.org/user/Plant.aspx?LatinName=Lactuca+virosa Traditional / reference
    https://pfaf.org/user/Plant.aspx?LatinName=Lactuca+virosa
  14. Ghasemzadeh Rahbardar, M. and Hosseinzadeh, H (2024) 'Therapeutic potential of hypnotic herbal medicines: A comprehensive review', Phytotherapy Research, 38(6), pp. 3037-3059. doi:10.1002/ptr.8201 Meta-analysis / review
    https://doi.org/10.1002/ptr.8201
  15. Block, K.I., Gyllenhaal, C. and Mead, M.N (2004) 'Safety and efficacy of herbal sedatives in cancer care', Integrative Cancer Therapies, 3(2), pp. 128-148. doi:10.1177/1534735404265003 Meta-analysis / review
    https://doi.org/10.1177/1534735404265003

This fact sheet is generated automatically from the Omnia Sana plant database and reflects its latest synced data. It is provided for educational purposes only and is not medical advice. How this site is built.

Selected studies & references

Educational use only. This profile summarises traditional and scientific sources for reference. It is not medical advice and not a substitute for a qualified practitioner. Some plants carry safety cautions and drug interactions - always check before use.
This profile is assembled automatically from the Omnia Sana plant database, which we curate by hand. How this site is built.
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