There's a very specific childhood memory most of us share, somewhere in a hedge in summer: the sharp, disproportionate outrage of a nettle sting, followed immediately — without anyone ever teaching us to do it — by frantically rubbing the spot. Some households go further and send you off in search of a dock leaf, which does, for the record, absolutely nothing chemically useful. It is a placebo with good PR.
What's odd isn't the sting. It's the rubbing. Nobody sat you down and explained the physiology. You just did it, and it just helped, and you never thought about it again — filed under "things that are simply true," along with gravity and the offside rule.
Turns out the rubbing thing is a small, low-stakes demonstration of one of the more interesting ideas in pain science, and it has a fairly direct line to what happens on my treatment table. So bear with me — we're going from hedgerows to spinal cords to, somewhat improbably, deliberately stinging arthritic joints with nettles on purpose. It gets there.
In the 1960s, Melzack and Wall proposed what's known as gate control theory, which — stripped of the diagrams — says something like this: pain signals and touch signals both queue up at the same junction in your spinal cord before being allowed through to the brain. Touch signals travel faster. And there's only so much room at the gate.
So when you rub a nettle sting, you're flooding that junction with big, fast touch signals, which get through first and effectively close the gate before the slower, whinier pain signal arrives to make its case. The pain isn't cured. It's queue-jumped.
Which tells you something useful and slightly humbling about pain generally: it isn't a direct, honest read-out of tissue damage being beamed straight to your brain. It's a story your nervous system tells you, edited on the way, with certain things prioritised and others quietly left out. That's not a design flaw. A nervous system that reported every single sensation with equal weight, all the time, would be useless — you'd never get anything done. So it triages. Threats first. Everything else, filtered down or dropped entirely. Mostly it's a decent editor. Sometimes, particularly with pain that's hung around far longer than it's useful, it's an unreliable narrator with a flair for the dramatic.
A fair chunk of what happens in a chiropractic session — hands-on work, manipulation, mobilisation, the various things that make people go "ooh, that's better" — isn't purely about correcting some structural fault, however tidy that story is to tell. What I'm actually doing, most of the time, is restoring normal function to systems that have stopped doing their job properly — joints, fascia, muscle, the nervous system itself. And a meaningful part of how that works is leaning directly on this same gate. Touch and movement, delivered in the right way, jostling for space on the same narrow path and, more often than not, shoving pain clean off the edge.
I don't think that's a lesser explanation. It's a perfectly good one, and being honest about it seems more useful to patients than pretending every adjustment is realigning something that had gone rogue. Sometimes it's simpler than that: it's your nervous system being handed a more convincing story to run with.
Here's where the history gets properly interesting. Long before anyone had heard of gate control theory, people were treating arthritic joints by stinging them with nettles on purpose. Deliberately. This is called urtication, and it's not a fringe curiosity — it turns up across centuries and cultures as a folk treatment for joint pain, and small modern trials have found it does genuinely seem to reduce pain in some people with osteoarthritis.
So somewhere back down the generations, someone worked out — almost certainly by accident, quite possibly by falling into a hedge — that stinging a bad joint on purpose could make it feel better, and it stuck around as a remedy for a few hundred years before anyone could say why. Modern pain science eventually turned up and, essentially, confirmed the hedge was right all along.
Not, to be clear, take up nettle-stinging your own knees. That's not really the point, and I'd rather you didn't email me about it.
The point is this: a decent slice of what makes pain better — including some of what happens in clinic — isn't about repairing damage in the way people imagine, it's about restoring function by changing the signal your nervous system decides to prioritise. That's not a trick, and it isn't "it's all in your head" dressed up in nicer language either. It's just how the system is built, and placebo — genuinely, not as an insult — is part of that same system doing its job. Once you know that, a lot of "why on earth would that help" treatments — heat, movement, touch, even a nettle sting — stop seeming mysterious and start seeming like exactly what you'd expect, given what pain actually is.
Your nervous system has been quietly editing your reality for your entire life, mostly for your own good. The nettle sting is just one of the rare moments you can catch it in the act.
