Prickly Lettuce

This genus contains about 100 species of annuals and perennials, which occur worldwide, especially in northern temperate regions. Lactuca serriola originated in Europe; it is more like a sow thistle (Sonchus spp.) than a garden lettuce (L. sativa) and has little to recommend it as an ornamental or culinary plant. Lactuca specie contain mildly narcotic compounds in the latex, known as "lactucarium" when dried. The active constituents increase during flowering and are relatively low in young plants. Lactucarium entered medical practice as a sedative in the 18th century. It used to adulterate opium (Papaver somniferum, See, Opium Poppy) and was known as "lettuce opium" because of its similar, but non-addictive, effects. In addition to L. serriola, the main sources of lactucarium are L. canadensis (American wild lettuce) and L. virosa (wild or great lettuce). Centuries of breeding have reduced the amounts in the garden lettuce (L. sativa). Lactuca is from the Latin lac, "milk", and refers to the milky sap (latex), source of lactucarium.

Related to garden lettuce, this wild variation contains a milky substance referred to as lettuce opium, because it has some properties similar to the opium taken from poppies. Used as a sedative, wild lettuce reportedly eases restlessness, anxiety, and insomnia and has been used in place of opium in cough preparations.

Fetid, hairless annual or biennial with prickly stems and prickly, glaucous leaves, to 30cm (12in). Yellow flowers, resembling miniature dandelions, appear in panicles in summer.

Common Name:
Prickly Lettuce
Other Names:
Acrid Lettuce, Bitter Lettuce, Green Endive, Lactucarium, Lettuce Opium, Poison Lettuce, Compass Plant, Wild Lettuce
Botanical Name:
Lactuca serriola syn. Lactuca virosa
Native Location:
Well-drained to dry, alkaline soil in sun
By seed sown in situ in autumn.
Latex is extracted from leaves and stems of flowering plants in summer and dried for use as lactucarium and in extracts, infusions, tablets, and tinctures.
1-1.5m (3-5ft)
30cm-1m (12-36in)
Parts Used:
Whole plant, leaves, latex.
A very bitter, sedative, expectorant herbs with an unpleasant smell, that relieves pain, and soothes irritated tissues.
Medicinal Uses:
Internally for insomnia, anxiety, neuroses, hyperactivity in children, dry coughs, bronchitis, whooping cough, and rheumatic pain. Combined with Cypripedium parviflorum var. pubescens (See, Greater Yellow Lady's Slipper), Humulus lupulus (See, hops), Passiflora incarnata (See, maypops), Scutellaria lateriflora (See, Virginia Scullcap), and Valeriana officinalis (See, valerian) for insomnia. Causes drowsiness; excess causes restlessness.
To treat diseases of the urinary tract, asthma, whooping cough, painful menses, and nymphomania.
Typical Dose:
A typical dose of wild lettuce may range from 0.5 to 3.0 gm of the dried leaves.
Possible Side Effects:
Wild lettuce's side effects include sweating, dizziness, rapid heartbeat, and ringing in the ears.
Drug Interactions:
Takign wild lettuce with these drugs may increase the therapeutic and/or adverse effects of the drug:
Acetaminophen and Codeine, (Capital and Codeine, Tylenol with Codeine)
Alfentanil, (Alfenta)
Alprazolam, (Apo-Alpraz, Xanax)
Amobarbital, (Amytal)
Amobarbital and Secobarbital, (Tuinal)
Aspirin and Codeine, (Coryphen Codeine)
Belladonna and Opium, (B&O Supprettes)
Bromazepam, (Apo-Bromazepam, Gen-Bromazepam)
Brotizolam, (Lendorm, Sintonal)
Buprenorphine, (Buprenex, Subutex)
Buprenorphine and Naloxone, (Suboxone)
Butabarbital, (Butisol Sodium)
Butalbital, Acetaminophen and Caffeine, (Esgic, Fioricet)
Butalbital, Aspirin and Caffeine, (Fiorinal)
Butorphanol, (Apo-Butorphanol, Stadol)
Chloral Hydrate, (Aquachloral Supprettes, Somnote)
Chlordiazepoxide, (Apo-Chlordiazepoxide, Librium)
Clobazam, (Alti-Clobazam, Frisium)
Clonazepam, (Klonopin, Rivotril)
Clorazepate, (Tranxene, T-Tab)
Codeine, (Codeine Contin)
Dexmedetomidine, (Precedex)
Diazepam, (Apo-Diazepam, Valium)
Dihydrocodeine, Aspirin, and Caffeine, (Synalgos-DC)
Diphenhydramine, (Benadryl Allergy, Nytol)
Estazolam, (ProSom)
Fentanyl, (Actiq, Duragesic)
Flurazepam, (Apo-Flurazepam, Dalmane)
Glutethimide, (Glutethimide)
Haloperidol, (Haldol, Novo-Peridol)
Hydrocodone and Acetaminophen, (Vicodin, Zydone)
Hydrocodone and Aspirin, (Damason-P)
Hydrocodone and Ibuprofen, (Vicoprofen)
Hydromorphone, (Dilaudid, PMS-Hydromorphone)
Hydroxyzine, (Atarax, Vistaril)
Levomethadyl Acetate Hydrochloride, (Levomethadyl Acetate Hydrochloride)
Levorphanol, (Levo-Dromoran)
Loprazolam, (Dormonoct, Havlane)
Lorazepam, (Ativan, Nu-Loraz)
Meperidine, (Demerol, Meperitab)
Meperidine and Promethazine, (Meperidine and Promethazine)
Mephobarbital, (Mebaral)
Methadone, (Dolophine, Methadose)
Methohexital, (Brevital, Brevital Sodium)
Midazolam, (Apo-Midazolam, Versed)
Morphine Sulfate, (Kadian, MS Contin)
Nalbuphine, (Nubain)
Opium Tincture, (Opium Tincture)
Oxycodone, (OxyContin, Roxicodone)
Oxycodone and Acetaminophen, (Endocet, Percocet)
Oxycodone and Aspirin, (Endodan, Percodan)
Oxymorphone, (Numorphan)
Paregoric, (Paregoric)
Pentazocine, (Talwin)
Pentobarbital, (Nembutal)
Phenobarbital, (Luminal Sodium, PMS-Phenobarbital)
Phenoperidine, (Phenoperidine)
Prazepam, (Prazepam)
Primidone, (Apo-Primidone, Mysoline)
Promethazine, (Phenergan)
Propofol, (Diprivan)
Propoxyphene, (Darvon, Darvon-N)
Propoxyphene and Acetominophen, (Darvocet-N 50, Darvocet-N 100)
Propoxyphene, Aspirin, and Caffeine, (Darvon Compound)
Quazepam, (Doral)
Remifentanil, (Ultiva)
Secobarbital, (Seconal)
Sodium Oxybate, (Xyrem)
Sufentanil, (Sufenta)
S-Zopiclone, (Lunesta)
Temazepam, (Novo-Temazepam, Restoril)
Tetrazepam, (Mobiforton, Musapam)
Thiopental, (Pentothal)
Triazolam, (Apo-Triazo, Halcion)
Zaleplon, (Sonata, Stamoc)
Zolpidem, (Ambien)
Zopiclone, (Alti-Zopiclone, Gen-Zopiclone)
Disease Effects:
May worsen cases of benign prostatic hyperplasia (BPH) and narrow-angle glaucoma, due to hyoscyamine content.
Supplement Interactions:
  • Increased risk of bleeding when used with herbs and supplements that might affect platelet aggregation.
  • May enhance therapeutic and adverse effects of herbs and supplements that have sedative properties, such as 5-HTP, Kava Kava, St. John's Wort, and Valerian.
Culinary Uses:
Young leaves are eaten raw in salads or cooked as a vegetable. Seeds yield edible Egyptian lettuce seed oil.
Encyclopedia of Herbs by Deni Brown Copyright © 1995, 2001 Dorling Kindersley Limited Pg 250
The Essential Herb-Drug-Vitamin Interaction Guide by Geo. T. Grossberg,MD and Barry Fox,PhD Copyright©2007 Barry Fox,PhD. Pp.489-491