Wild lettuce (Lactuca virosa) is a plant grown in the United Kingdom, South Asia, and North America. It has been studied for sedative and analgesic (pain-relieving) effects and for its effects on nerve activity.
Wild lettuce is part of the Asteraceae (Compositae) family and is closely related to dandelion. It is not consumed raw, but it can be consumed as a dietary supplement, usually in capsule or extract form.
In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says. When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.
Verywell / Getty Images
What Is Wild Lettuce and What Does It Do?
Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.
Wild lettuce is a plant or weed that is similar to sowthistle and dandelion. It is sometimes used as an herbal supplement. It can be found in central and southern Europe, Australia, the Punjab region of India and Pakistan, and along the coast of Great Britain.
Wild lettuce contains two main compounds—lactucin and lactucopicrin—that act on the central nervous system. Wild lettuce has the highest concentration of lactucopicrin of all plants, although dandelion and chicory roots are also sources.
In addition to its sedative and analgesic effects, lactucopicrin is believed to act as an acetylcholinesterase inhibitor; this means that it blocks cholinesterase enzymes responsible for slowing communication between nerve cells. Wild lettuce is also said to kill many bacteria, viruses, fungi, and other microorganisms.
Despite the health claims, there is little evidence that wild lettuce can prevent or treat any medical condition. Most research is limited to small, low-quality studies or studies in animals only.
Effects on Nerves
Wild lettuce appears to be a robust acetylcholinesterase inhibitor. Acetylcholinesterase is an enzyme that stops certain types of nerve activity. Acetylcholinesterase inhibition prolongs nerve activity.
Additionally, a study found that lactucopicrin increased neuritogenesis in brain cells extracted from lab rats. Neuritogenesis is when nerve cells sprout projections, called neurites, that connect one nerve cell to another. The more neurites there are, the stronger the sending of nerve signals.
Further human research is needed to see whether wild lettuce has practical application in neurodegenerative diseases (diseases impacting the brain and nerves).
Does Wild Lettuce Work for Pain Relief?
Little research has been conducted to support the use of wild lettuce for pain symptoms.
In one study, researchers gave lab mice either lactucin, lactucopicrin, or ibuprofen (a nonsteroidal anti-inflammatory drug) in oral form. The mice were then subjected to a hot-plate test and a flick-tail test (in which their tails were flicked) to assess their response to pain.
Of the compounds tested, lactucopicrin was the most potent and required half the dose compared to ibuprofen. Lactucin and lactucopicrin also appeared to have a sedating effect, as evidenced by slowing the animals’ reflexes. Further study in humans would be needed to confirm these results.
What Are the Side Effects of Wild Lettuce?
The long-term safety of wild lettuce is unknown. Wild lettuce is generally considered safe if consumed in reasonable amounts, although it may cause mild indigestion, jitteriness, or drowsiness.
Some people may experience skin irritation if wild lettuce is applied to the skin. This is especially true for people with a latex allergy. Avoid use in people allergic to wild lettuce or its components.
A 2009 study detailed eight incidences of poisoning after consuming large quantities of raw wild lettuce.
Common Side Effects
Common side effects include but aren’t limited to:
- Chills or sweating
- Stomach pain
- Back and neck pain
- Headaches and dizziness
- Nausea and vomiting
Severe Side Effects
These side effects can occur at any time while taking wild lettuce. If you experience these symptoms, stop using wild lettuce and seek immediate medical attention for the following:
- Loss of consciousness
- Blurred vision and/or extreme sensitivity to light
- Sweating
- Hallucinations
- Urinary retention
- Heart complications
If you’re having a severe allergic reaction or if any of your symptoms feel life-threatening, call 911 and get medical help right away.
Precautions
Due to potential harm, wild lettuce should not be used by:
- Pregnant or breastfeeding people
- Children
- People who are immunocompromised
- Pets
Dosage: How Much Wild Lettuce Should I Take?
Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your individual needs.
There are no guidelines for the appropriate use of wild lettuce, but manufacturers of capsule formulations typically recommend 400 to 500 milligrams (mg) per day. As a general rule, never exceed the dose on the product label.
Taking 12–24 drops two or three times daily has been suggested for tincture preparations.
Supplement Facts
- Active Ingredient(s): Lactucin, lactucopicrin
- Alternate Names(s): Bitter lettuce, opium lettuce, poisonous lettuce, rekutu-kayumu-so
- Legal Status: Over-the-counter (OTC) dietary supplement (United States)
- Suggested Dose: No guidelines for appropriate dose; manufacturers suggest 400–500 milligrams (mg) per day for capsules and 12–24 drops, two or three times daily, for tincture
- Safety Considerations: Avoid use when pregnant or breastfeeding, or in children; avoid with medications, herbs, supplements, or beverages with a sedative effect, including alcohol, opioids, or antihistamines like Benadryl (diphenhydramine)
What Happens If I Take Too Much Wild Lettuce?
Toxicity from wild lettuce supplementation is possible. Toxicity occurs when the active ingredient in a supplement builds up in the body over time, causing negative health effects.
It is not yet understood if an overdose of wild lettuce is possible.
Interactions
Cholinesterase inhibitors can sometimes cause or worsen angle-closure glaucoma. Since wild lettuce blocks cholinesterase enzymes, it may cause or worsen narrow-angle glaucoma.
You should avoid wild lettuce if you are taking sedatives or any sedating substance, including alcohol, opioids, or antihistamines like Benadryl (diphenhydramine), or other sedating herbs or supplements.
It is essential to carefully read a supplement’s ingredients list and nutrition facts panel to learn which ingredients are in the product and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.
Similar Supplements
Similar supplements include but are not limited to the following:
White willow bark is thought to soothe the joint pain associated with osteoarthritis, while devil’s claw is used to reduce pain caused by rheumatoid arthritis. Others use cannabidiol, also known as CBD oil, the non-psychoactive compound in marijuana.
Check with your healthcare provider before using any supplement or herb to treat pain.
Sources of Wild Lettuce and What to Look For
Wild lettuce plants can reach 3 to 8 feet in height. It has green leaves and pale yellow flowers. The seeds are attached to a pappus that resembles the puffy white “fluff” of a dandelion. It is not recommended to procure wild lettuce on your own.
Food Sources of Wild Lettuce
Due to the risk of toxicity, raw wild lettuce should not be consumed. Even though the plant is uncommon in the United States, it reportedly has been introduced in parts of California and Alabama.
Wild Lettuce Supplements
Wild lettuce can be found online and in stores that sell supplements. It is sold in capsule form, dried herbs, liquid extracts, and powders.
Dried herbal and powdered formulations can be used to make tea by steeping one to two tablespoons of the dried herb or one to two teaspoons of the powder into a cup of boiling water.
Caution should be used when working with dried Lactuca virosa as you might not be able to control the dose and may consume more than you realize. Moreover, there is no way to know if the dried herbs have been tainted with pesticides, heavy metals, chemical fertilizers, or other harmful substances.
Summary
Wild lettuce (Lactuca virosa) is a plant used to relieve pain and prevent or treat symptoms of various unrelated medical conditions, including anxiety, arthritis, insomnia, cough, and menstrual pain.
Little evidence exists that wild lettuce can prevent or treat any medical condition. Before using it, please speak with your healthcare provider about any questions or concerns.
Wild lettuce is generally considered safe but may cause reactions in people with a latex allergy. It may build up in the body over time, causing negative health effects. When used in excess, wild lettuce can lead to toxicity and poisoning.
In the short term, wild lettuce can also cause drowsiness and should not be used with alcohol or sedatives.
There is no clinically recommended dose for wild lettuce. To ensure purity, opt for brands certified by third-party organizations like USP, NSF, or ConsumerLab.
