How do Stinging Nettles Inject Poison?

The leaves of stinging nettles are covered in 'pipette-like' stingers which penetrate the skin on contact and deposit a small amount of poison. The 'pipette-like' design means that almost all of the poison contained in the stinger can be injected at once if sufficient force is applied to bend the stinger to an angle of 90 degrees. This is demonstrated in laboratory experiments conducted by Kaare Jensen at the Technical University of Denmark. Interview with University of Oxford Mathematician Dr Tom Crawford.

This video is part of a collaboration between FYFD and the Journal of Fluid Mechanics featuring a series of interviews with researchers from the APS DFD 2017 conference.

Sponsored by FYFD, the Journal of Fluid Mechanics, and the UK Fluids Network. Produced by Tom Crawford and Nicole Sharp with assistance from A.J. Fillo.

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The techniques employed by plants and animals to defend themselves are very varied. Some involve extremely refined armaments. Stinging nettles employ hollow needle-like stinging hairs constructed from silica, the mineral from which we make glass, and they are filled with poison. The hairs are remarkably rigid and rarely break. Yet the tip is so sharp that the slightest touch cuts human skin, and so fragile that it breaks at that touch and releases poison into the wound. How the seemingly antagonist mechanical functions of rigidity and fragility are achieved, however, is unknown. We combine experiments on real and synthetic stingers to elucidate the poison injection mechanism. The design of plant stingers is compared to other natural systems and optimal stinging strategies are discussed.

Nature Publication:

JFM Publication:
'Viscous flow in a soft valve' K Park, A Tixier, AH Christensen, SF Arnbjerg-Nielsen… - Journal of Fluid Mechanics, 2018

Special Thanks To:
Nicole Sharp
A. J. Fillo
Kaare Jensen
Whatcom Community College

[HarrisonBradke]

I saw a video where a guy jumps into a bush of them so I came here to see what happens when you get stung

[miksumasterjbl]

They are not poisonous.
Those chemicals do hurt, but they're not poison.
If there is too much chemicals, then it becomes poisonous.
If they were poisonous, i would be dead already. Well, am i dead? Nope, i am still alive.

I love nettles, I eat them every summer. They're very good for your health, you just need to prepare them first, before eating, if you don't want to get stung.
Some people can eat them raw, like me. I love raw nettles.
It hurts, but i ingnore the pain.

My blood is healthy, because i eat nettles.
I don't need any useless medication.

[joakimborjesson]

People from Sweden knows what this is ;) it hurts really bad

[xokizza]

Well I didn’t know about this now my finger is all numb it’s so annoying ...

[zepher_blackstoc]

I'm here because I got stung and I want to know it works.

[alexisbruv]

i see you don’t know what the tgf thing is but it’s basically three guys messing around with nettle

[untitled]

So my friends help me still and stung me with a nettle so for revenge I'm gonna do it back >:) quick question tho, is it possible to empty the poison into a cup?

[SanniGD]

I don't know how,


But i somehow got here.

[CobDaGOAT]

Today I tried to remove a nettle from the ground with my bare hand. I wont be doing that again.

[the_gamer_kinda]

I fell earlier and my hand landed on one... I'm hurting

[mzalenski]

Not trying to be "that guy", but wouldnt it be considered "venom" due to the fact that its injected?

[keshvee]

When a student was stung by a nettle plant the teacher applied an aqueous solution of ammonia to the affected area of the skin to relieve the place... explain

[kBTVP]

My third time gliding by a bull nettle.... And I still have a reaction 3 weeks later. I guess it got me good! Eeeeek

[zar]

I went to a hike for the first time and got stinged by these plants that i dont even know exist. I put my hands in water and it feels like its being clawd by Satan himself.

[faithnaidoo]

IS THERE A STINGLE NETTLE THAT IS POISONOUS TO CONSUME???

[GooglyBlooglyOfficial]

i still cant forget the salad finger episode... 💀💀💀💀

[kristinporter]

Why are you calling it POISON ??? Define POISON.

[Sutty]

I've never been affected by nettles

[juliejames]

Poison is incorrect. The chemistry of nettle is absolutely not poisonous. Curious that you seem to be scientifically oriented and yet use such an inappropriate word.