Wild Lettuce Revisited, Week Ending 8/2/2020

I’ve been giving much thought lately to the matter of wild lettuce.

And am amazed by how little I still know about the plants growing around us in nature.

I wanted to experiment with using wild lettuce for its pain killing effects, but needed to learn more first. First and foremost, I couldn’t find any definitive answer about which wild lettuce to use.

In fact, I hadn’t even realized there was more than one type of wild lettuce!

I re-read the lettuce chapter in Sam Thayer’s Nature’s Garden. He doesn’t discuss medicinal uses for the plants, only their edibility. He makes no mention of Lactuca virosa which is the wild lettuce variety most commonly associated with pain relief (it’s sometimes even called “opium lettuce”). I thought perhaps L. canadensis was actually the same thing, but I’ve found multiple websites referring to them as distinct species.


The one thing I have discovered: the “wild lettuce” growing in my yard is actually prickly lettuce (L. serriola), the wild ancestor of modern garden variety lettuces (L. sativa). The leaves have a more aggressive row of spines on the bottom; feature a more bluish color with a pale midrib; and tend to turn towards the sun so most of them will be flat on stalk because they are all facing the same way.

The extra-spiky midrib of a prickly lettuce leaf
The extra-spiky midrib of a prickly lettuce leaf

Since sources seemed to disagree about whether L. serriola could be used for medicinal purposes I decided to give it a try to find out for myself. Of course I am not a trained herbalist nor a medical professional, so the only thing I’m describing here is my own experimentation. Do NOT do something just because I’m doing it – do your own research, my friends!

I sort-of-ish followed the approach in this article I linked to several weeks ago. At least in spirit. OK not really. At least I waited until they were starting to flower.

Prickly lettuce starting to flower
Prickly lettuce starting to flower

I don’t know whether this timing is because they are at their largest – hence producing the most sap – or if something about flowering enhances the effects of lactucarium (the sap we’re collecting). I picked three tall plants, cut off the leaves, and then proceeded to snip bits off them, an inch or so at a time, waiting in between cuts for the sap to have a chance to well up.

Lactuarium, the milky sap we're harvesting, welling up from the cut stem
Lactucarium, the milky sap we’re harvesting, welling up from the cut stem

Rather than wiping the sap on a bowl to dry, I dropped the bits of stem into 200 mL of high proof alcohol, because the active ingredients are apparently soluble in alcohol. As more of the prickly lettuce plants reach the stage where I can harvest them, I will add to the jar. Three plants didn’t produce very much!

(Although one wonders if the pain relief / sedative effects of my tincture will be from the lactucarium, or the high proof alcohol!)

I also consulted this article about harvesting and preparing wild lettuce for medicinal use. I felt like the author’s approach was very thorough, but perhaps overkill for my own little experiment. I was also intrigued that the author opted to use L. biennis for the medicine, because so many other websites focused on L. virosa for this purpose. I wish they had written more of an update on how it went. Because remember my lettuce misidentification from several weeks ago? A giant plant I thought was lettuce, but how could it be since it was SO very tall?

Meet L. biennis, aka tall blue lettuce.

Tall blue lettuce towers over my head
Tall blue lettuce towers over my head

Like, really tall. Probably over seven feet, if I were to guess. If I can harvest sap from this plant, I’d probably have enough to last a lifetime! And there were several other plants close by. Unfortunately they weren’t flowering yet, so I’m going to give them a few more weeks before attempting to harvest the sap, using the same multiple-cuts-down-the-stalk approach as I used for the prickly lettuce.

And L. virosa? The lettuce I supposedly want above all others for medicinal use? I’m not sure it exists around here! Strangely, the Maryland Biodiversity Project doesn’t even include the species. Just like Sam Thayer made no mention of it… I guess more research is in order!


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