Stinging Nettle Urtica dioica: Some Interesting Uses
I remember like it was yesterday, cycling out of control through a thick nettle patch, tangling, stalling, and falling in amongst the stingers. Worst thing was I was wearing only shorts and T-shirt! As a young lad it was an excruciating introduction to a plant that in later life I would grow to love. Nowadays it makes regular appearances in my survival and bushcraft courses.
The extraordinary thing about the stinging nettle is that it is so well known and common, and yet so under-rated. Well, they say familiarity breeds contempt. Right there on our doorstep we have an incredible natural resource, free to those who dare approach it, yet many people ignore it or just don't know its worth.
So, what is so special about the stinging nettle? Let's start with what it is famous for - stinging! Obviously the sting is the plant's defence - the whole plant is covered in them. While they certainly hurt, there is a traditional idea that getting stung can sometimes do us some good. The Roman's believed it. They brought the plant with them and used the analgesic affect of the stings to sooth the aching limbs of their soldiers. There is even a technical name for stinging yourself deliberately - "urtication". I know it sounds a bit far fetched that stinging yourself can help with pain, however, a controlled scientific trial lends credibility to the idea.
Randall and colleagues took 27 people with arthritic thumb or finger pain - half the group were given stinging nettle to apply and the other half were given white dead nettle (Randall et al., 2000). The dead nettle was the placebo - it looks like a stinger when not in flower but doesn't sting. Subjects were told that they might experience a sting but that the scientists were investigating both plants. After a week of treatment the groups took a 5 week break before swapping to the other kind of nettle. The subjects scored their joint pain and disability levels at each stage. Long story short, the pain and disability scores decreased significantly with stinging nettles versus the placebo. One theory is that it may work a bit like a TENS machine (light electric shock) used to manage pain during child birth. Hyper-stimulation of the pain receptors ("nociceptors") deflects the greater pain. Although many people would recoil at the notion of urtication, those taking part in the experiments generally said they got use to it and valued the net benefit, even recruiting friends and relatives to try it (Randall et al., 1999).
Anyway, so I'm back lying beside my bike in the nettles...I'm not exactly thinking "this could do me some good!". I frantically search for a dock leaf and rub it all over the rash with zeal. It definitely seems to soothe the myriad of burning stings...
On my bushcraft courses I often get asked - "does a dock leaf really help with nettle stings?" Funny thing is, I always thought it did. I even read that dock neutralises the formic acid in the sting. It all seemed to add up. But like most things, the devil is in the detail. As I started sifting through scientific papers on nettle stinging (yes such papers do exist!) the simple story began to deconstruct. Turns out dock is not alkaline but acidic too. Turns out nettle stings are a lot more than just acid. Yes there is acid in there for sure - formic acid, oxalic acid, tartaric acid but probably too little to hurt. The more likely suspects in the conspiracy of pain are the neurotransmitters - acetylcholine, serotonin and histamine. These are known to cause inflammation and fire up pain receptors. In fact, if you inject histamine it is supposed to cause a similar rash and pain to nettle (but don't try this at home!).
Isn't it funny how psychology works though. Even with all this new information something in me resisted the idea that dock is really no use with nettle stings. Perhaps the bike experience forged a deep cognitive connection? So I had to know. I decided to undertake a mini experiment of my own. I would sting the inside of each arm and rub dock into the stings on one arm and just rub the other with my hand. Whatever the result it may at least cure my tennis elbow, I told myself!
When I applied the dock at first it felt cool and soothing in a way that just rubbing did not. However within a minute or so I could not detect any difference between the two arms - either in pain or appearance of the rash. Both rashes first got more livid and raised with a prickling sensation and then slowly receded over a few hours. However, at no point was there a clear difference between the two arms. So although not exactly deep science, I can say with reasonable confidence that the dock did not help the stings except for the initial cooling. You might have thought case closed...but no, then I had another thought. If histamine is the main culprit in the sting would a plant thought to have anti-histamine properties be more effective than dock? I was thinking hedge woundwort. However on repeating the experiment with woundwort there was again no difference. I will probably come up with other ideas and report them if I get any positive benefits. In the meantime I now have a better answer on to give my courses. Just bear in mind that some people are more sensitive to nettle stings than others, so proceed carefully with experiments in urtication.
Nettles are also good to eat when the shoots are young, but best avoided later in the season when uric acid accumulates in the dry leaves. It makes a good spinach substitute and is rich in vitamins B, C, K and minerals such as calcium, iron, magnesium, phosphorus, potassium and sodium. Sometimes on courses we wilt the plant next to the fire which neutralises the stings and makes them crispy and tasty. Nettle tea is also a survival course favourite. Best to steep a small handful of leaves in a cup of hot water.
With nettle you are not just getting good nutrition, you also have a powerful medicine. A review paper lists over 100 medicinal uses of nettles worldwide (Joshi et al., 2014). Obviously we can't vouch for all of them, but let's look at a few important ones with scientific support.
Chemical tests by Gülçin and colleagues have shown that nettle has anti-oxidant, anti-microbial, anti-ulcer and analgesic activities (Gülçin et al., 2004). We have already discussed analgesic benefits of stings on achy joints, but experiments on mice (which I don't condone by the way) suggest some pain relief benefits may also be accrued by ingesting the extract of the leaves.
Anti-oxidant effects of nettles are also important as cancer is in the top 10 causes of mortality worldwide. Free radicals which are produced in the normal process of metabolism can cause DNA damage leading to cancers, particularly when combined with environmental carcinogens. Nettle extract has been shown to collect and inactivate free radicals and also similarly act as chelating agent for excess metals in the blood. This may reduce our cancer risk if taken regularly.
Bacterial infections used to be a major cause of mortality before the discovery of anti-biotics. Today the overuse and inappropriate use of anti-biotics is producing anti-biotic resistance, for example in super-bugs such as MRSA. It can be argued that natural anti-microbial agents like nettle should be a first port of call for bacterial maladies are not life-threatening. Impressively, nettle extract has been shown to have a substantial anti-microbial effect. For microbes like E.coli, Staphilococcus, Streptococcus, Proteus and Enterobacter, nettle extract has been shown to perform 30-75% (in vitro) as effectively as pharmaceutical anti-biotics (e.g. Amoxicillin, Ofloxacin). Also, nettle has anti-viral and anti-fungal properties which can't be said anti-biotics. For example it is good for treating fungal Candida infections (40% as effective, in vitro, as some pharmaceutical treatments) (Gülçin et al., 2004)
Nettle is also a mild diuretic, so it helps flush the urinary system. Put together with its anti-microbial and chelating properties you can see why it is well known for detox and treating urinary infections.
There is so much more that can be said about nettle and its uses, but I have to finish by mentioning its value as a fibre. On survival courses we often use nettle fibres for making string - it is great for fishing lines, snares, nets, bow strings etc. The fibres are in the outer skin of the nettle stem. I have made a short video on how to harvest nettle fibres and make cord with them. The fibres are very strong and have reasonable elasticity. They have even been harvested and woven to make clothing commercially. Interestingly nettle is also a promising natural fibre for use in biodegradable composite material. Per density it appears to have higher stiffness, strength and, strain to failure ratings than plastic glass fibres (Bodros and Baley, 2008). This could help with the problem of microplastic pollution.
So you can see nettles are really extraordinary plants deserving of our respect. They make for nutritious food, drinks, medicines, fibres, clothing, sting therapy and a lot more. Oh yes, but if you do fall into a nettle patch don't rely on dock to take away your pain!
P.S. Here's the video which we made specially for those lovely folks from the Green Crafts Village, who we would normally be working with at Glastonbury Festival at this time of year. Here's to next summer!
Randall, C., Randall, H., Dobbs, F., Hutton, C., & Sanders, H. (2000). Randomized controlled trial of nettle sting for treatment of base-of-thumb pain. Journal of the Royal Society of Medicine, 93(6), 305–309