Horse reactions to stinging nettle (Road to Tevis #64)

Last Friday I learned all about horse reactions to stinging nettle, after a lifetime of ignoring their potential danger

Above: Fantazia and I came through that gap in the nettles out of a stream bed.

Identifying stinging nettle

The Latin name for stinging nettle (aka common nettle, burn nettle, stinger…) is urtica dioica. It’s invasive in the Americas. The plants are perennial, though they die down a bit in winter. They grow up to 6-7 feet tall, and have nasty stinging hairs on them. Not all tha many hairs on their leaves and stems sting, but enough do! These nasty little things not only pierce the skin, they also introduce biochemicals such as histamines, formic acid, serotonin, and acetylcholine (info in the wiki page and here on health.com). The rash and pain probably offsets any beneficial effect of microscopic quantities of serotonin 😉

Stinging nettle is not to be confused with horsenettle, a type of nightshade. Horsenettle is poisonous if ingested, but contact does not damage. Horses usually won’t eat enough of it to get sick unless they are on poor pasture and hungry.

Above: Left, stinging nettle. Right, dwarf nettle.

Some people (myself included) also refer to dwarf nettle as “stinging nettle.” Dwarf or small nettle is also an invasive species native to Eurasia. It’s smaller, greener, and softer than true stinging nettle. It does sting… a bit! You can grab some leaves, crush them, and rub them on the sting and it will go away. It does nothing to horses.

Benefits of stinging nettle

Stinging nettle has been used therapeutically for hundreds of years to treat many different disorders, including hypertension, diabetes, and arthritis (Dhouibi et al., 2019; Mount Sinai page; WebMd). It has been used in animals to promote growth in meat animals and as preventative and curative medicine (de Vico, Guida, & Carella, 2018).

Livestock (including horses) can eat dried nettle, which is nutritious.

Cooked stinging nettle is edible, healthy, and actually tastes good (I’ve eaten it in Spain). You can saute it (recipe) or make Nettle Soup (recipe). You can find no fewer than EIGHT stinging nettle recipes here.

Stinging nettle tea has many potential health benefits. You can make your own (free if risky), or you can buy it in bags or loose leaf. Those links are for cheaper versions on Amazon. Mountain Rose Herbs has nettle leaf tea from Europe and North America, as well as a plethora of other nettle products. I get my tea from Upton Tea Imports… I’ve just searched their site, and they don’t have pure nettle tea, but it is part of this Summer Blend.

Possible horse reactions to stinging nettle

They become crazed with pain. My well-trained and obedient mare wouldn’t listen to the bosal when I was on her. I couldn’t lead her from the left side because she’d run into me. People have since told me stories of horses collapsing to the ground (and dying in a field of nettles). Throwing themselves onto their rider, into a rocky streambed, over backwards. Bucking, rearing, kicking…

Heart attack. Horse reactions to stinging nettles may look like a heart attack, as described in this report of a racehorse in the UK.

Hives, ala urticaria. This webpage makes specific mention of nettle rash, which may be accompanied by weakness, wobbliness, and/or lameness. Fantazia was not lame, but she was definitely weak and wobby.

Allergy and constipation. Not sure what they mean by “constipation”. Impaction colic?

Ataxia, or loss of coordination, usually a symptom of a neurological disorder. See this veterinary record in pub med. Fantazia definitely exhibited ataxia.

Above: Left, you can see that stinging nettle grows freely along a boggy creek that runs through our cow pasture. The smaller dwarf nettles grow everywhere right now, including all along the fence line and in Fantazia’s paddock. Fortunately, they do not affect horses.

Fantazia’s reaction to stinging nettle

I managed to stop Fantazia when she ran sideways and backwards into a fence. As soon as she was still, I petted her. She was bent to the right, head up, trembling, and falling sideways. I slipped off. Her right hind leg was straightened, stiff, and falling from the hip towards her left hind. She was wobbly all over. When she managed to plant the right hind, she licked up her right fore and it began falling inwards. I took off the racing overgirth that was holding on the foam and sheet I had been riding on. (This set-up keeps my jeans from sweaty-horse-hair while being more comfy than a saddle for easy rides around the place. It also makes it easier to stay on a bolting sideways running horse!)

I thought she was having some sort of neurological crisis, imagining nerve damage around the SI. But when I started off towards the training barn, she began trotting, tail up, no limp (if a bit bent to the right). I jogged back to the barn with her trotting beside me. If I slowed to a walk, she’d start falling to the left (and on top of me). I still had no idea what was going on. She was covered with mud, so I took off her bosal–she fell against the fence as I did that, because stopped. At this point I texted my boyfriend that I needed help.

I took Fantazia into the wash rack to hose off the mud that was covering her legs up to knees and hocks and splattered over her belly and udder and up to her shoulder. She was still wobbly behind and bending to the right. At this point I noticed the wheals rising on her right forearm, lower shoulder, and gaskin. I realized it was the stinging nettle (because what else could it be?)

Above: A short video showing Fantazia’s reaction.

Treating horse reactions to stinging nettle

It turns out there isn’t much you can do.

Just as I took Fantazia out of the washrack, my boyfriend arrived. He’d never seen anything like it either. She was still bent to the right and ataxic behind. I texted my vet (who may regret giving me his cell number hahaha).

Then I googled “horse reactions to stinging nettle.” I clicked on the top google result; I recognized the web address as Kentucky Equine Research., Yes, they are selling stuff, but they’re still a trustworthy resource. The KER link had essential information:

1. “Horses have been reported to lean away from the affected side, repeatedly throw themselves to the ground, or collapse.” (check)
2. “Owners should be extremely cautious when leading or handling these horses, as they may jump, kick, pull away, break into a gallop, and collide with objects in their attempts to escape the unpleasant sensation.” (check)
3. “Treatment with pain relievers, corticosteroids, and antihistamines often provides little or no relief. Folk remedies including application of leaves, plant juices, mud, saliva, onions, white vinegar, or milk of magnesia are no more effective.” (ok)
4. “Mild sedation and turning the horse out into an area where it is relatively safe from self-injury are recommended.” (No sedative–Ace would have been good–but I could turn her out.)
5. “horses make a complete recovery within a few days to weeks.” (Fantazia was better the next morning.)

I immediately texted my vet not to worry, I’d figured it out, have a good weekend.

Then we turned Fantazia loose in the round pen (soft, safe, easy to catch) and observed her for five minutes. She pawed and kicked and was clearly uncomfortable but seemed sane, so I took her back to her pasture. When I first took the halter off, she turned around in little circles for a couple of minutes, then trotted away, as you can see in the video above.

She spent the next couple of hours trotting, with occasional breaks to paw, kick, or squeal at the geldings in the next pasture. By dinner she was calm enough to take a carrot and eat. When I went down to check on her at 9pm, she was standing quietly and had finished her feed.

Suggestions for ameliorating horse reactions to stinging nettle

Despite the discouraging information about possible treatments on Kentucky Equine Research, I asked for advice on the Equine Wellness Facebook page, and shared my nettle story on several more fora. That’s how I learned that about 2/3 of readers were as ignorant as I was about the dangers of stinging nettle. The other third had had similarly bad experiences (or even worse).

Very good advice I wish I had known

1. Keep the horse out of the sun.
2. Don’t put water on it. Fantazia didn’t mind me rinsing off the mud, but she didn’t want any further water on it. Apparently it makes it sting more.
3. In fact, some people suggested using mud to alleviate the pain, so I probably shouldn’t have rinsed it off. In my defense, I didn’t know what the problem was when I hosed her off!

Some suggested home remedies

Many people suggested remedies that they had used on themselves, other people, and/or horses. I’ll list some below, but I’d take them all with a grain of salt 😉

1. Benadryl. Apparently some horses will just eat people pills. I’d ask my vet about the quantity.
2. Dex. I did think about this but the stuff I’ve got on hand expired several years ago.
3. A few people suggested Jewelweed. Not sure how it would be used with horses but it’s pretty and has a history of use for stinging nettle by Native Americans. It doesn’t grow on our place, but I’m thinking we could try planting some!
   • Crush leaves and rub on welts
4. Several suggested lavender essential oil. I just know it’s poisonous to cats! (I used to use it to get rid of moths…)
   • 1 drop/2ml water, perhaps adding some vegetable oil. Saturate skin.
   • Smells good and probably wouldn’t hurt!
5. Paste of baking soda and water. I know that works for me with rashes.
6. Pee on in…. well. Perhaps if I were a man.
7. Plantain weed.
8. Burdock. The suggestion was to ball up a leaf and apply the juices to the wheals. Burdock is another one of those plants used extensively to treat all sorts of things in native medicines all over the world. I believe our bull thistle–which grows right beside the nettles–is in the same family so it might work. Anyway you can eat bull thistle.
9. Homeopathic remedy urtica urens. You’d need to know how to administer. I don’t in this case… but I did use homeopathy with my racehorses in Spain. It was effective. It still hasn’t really reached the USA though.

Fantazia’s recovery

Fantazia’s reaction to stinging nettle was gone within 24 hours. In the morning (about 16 hours post-exposure) she felt fine, but I could see the traces of wheals on her skin. By the afternoon, nothing. I didn’t ride for a few days just in case. On the third day, we did an arena work day. She was fine.

FAQ: Horse Reactions to Stinging Nettle

What is stinging nettle and how is it different from dwarf nettle?

Stinging nettle (Urtica dioica) has stiff, hollow hairs that inject irritants; dwarf nettle (Urtica urens) is smaller and typically causes milder stings. Both are common along damp areas.

Can stinging nettle harm horses on contact?

Yes. Contact can trigger intense pain, panic, wheals/hives, and transient ataxia or weakness. Most cases resolve with time and safe handling.

What signs should I watch for after exposure?

Sudden bolting or running sideways, collapsing, trembling, leaning away from the affected side, wheals on skin, and short-lived incoordination. (Horse might appear neurological.) Rule out other causes if signs persist.

What should I do immediately?

Move the horse to a safe, quiet, shady area; avoid crowding; handle calmly; and monitor until settled. Contact your vet if signs are severe, atypical, or prolonged.

Should I hose the affected areas?

Water can worsen stinging for some horses. If you must remove mud, rinse gently once, then keep the horse comfortable out of direct sun and avoid repeated washing.

Do antihistamines or steroids help?

Reports vary; many cases improve little with medication. Only use treatments under veterinary guidance and dose appropriately for equines.

How long does recovery take?

Most horses settle within hours and recover fully within 24–72 hours. Re-evaluate and call your vet if soreness, neurologic signs, or hives persist.

Is nettle ever safe for horses?

Dried nettle in forage and cooked nettle for humans can be safe and nutritious. The problem is fresh contact with stinging hairs.