I had a great weekend, thanks for ­asking. A bunch of like-minded souls and I got together in a frosty square in central London and took a massive overdose. Now, I should add at this point that I have not joined an extreme Christian cult (I couldn't – the Christian bit would upset my ­parents too much), and, as you can guess from the fact that I am writing this, the overdose was unsuccessful. I was at one of the many "mass homeopathic overdoses" taking place around the country to prove that homeopathy has as much effect on one's health as ­being hit in the face with a twig.

Whereas many of my fellow overdosers were protesting against the availability of homeopathic remedies at Boots, this doesn't bother me so much. If I felt outrage at the thought of Boots selling something that didn't live up to its promises, I'd have taken to the streets over several moisturisers years ago. ("Really? Literally reverse time?") What does offend me, though, is that this stuff is available on the NHS.

As a vegetarian who has been known to go to a fashion show and a yoga class in her time, I might seem a likely ­candidate for slapping on the arnica. But I feel about homeopathy the way Sarah Palin feels about climate change: shock that anyone in the modern world is daft enough to believe this rubbish. If I go to a fashion show or a yoga class, chances are I'll get a return on my investment: I'll see some fashion or I'll do some yoga. Buy a homeopathic remedy and will I be remedied? Maybe. But probably not. And unlike fashion shows, homeopathic treatments are available on the NHS, at a cost of £4m a year. This may seem a lot to anyone who has never been in a health food store; anyone who has will be saying, "They must have got one heck of a discount – honestly, last time I went in there to stock up on extract of cranberry, CQ10 vitamins and selenium supplements it cost me seven gajillion pounds."

A senior nurse makes at most £25,000 a year. Because I haven't been taking my Omega 3 supplements as regularly as I no doubt should, I can't work out how many more nurses the health service would be able to afford if it passed on the pollen extract without my brain exploding. But hopefully not for much longer. Next week a House of Commons select committee is publishing its findings on the use of ­homeopathy in the NHS. If this should turn out to be ­anything other than "please stop", I shall be tempted to pull a Billy Bragg and refuse to pay my ­income tax.

Inevitably, the homeopaths have been fighting their corner with a ­tenacity that belies their reliance on ­ineffective nutritional supplements and there has been much talk in the press about the value of garlic, ­cranberries and what have you. Here, the ­homeopaths don't actually help their case ­because cranberries/goji ­berries/insert name of this month's trendy fruit are very ­unlikely to be present in the final ­product because it has been so heavily diluted. Instead, homeopaths claim that the active ingredient imprints itself on the water's memory by a very special shaking ­process, a theory that sparks two obvious questions: if water has memory, does that mean vegetarians aren't allowed to drink it? And is this special shaking process similar to a ­toilet flushing? Because if so, ­presumably all drinking water must carry ­cherished memories of several generations of sewage. Pass the Evian.

Homeopathy styles itself as the ­caring, natural side of healthcare, ­removed from dangerous chemicals and nasty pharmaceutical companies. Quite how giving questionable hope with ­inflated price tags to people counts as caring or ­natural is never ­really ­explained. That homeopathy is ­promoted by the likes of Prince Charles is reason enough to be sceptical of it.

In a revealing ­moment, Senator Tom Harkin, the man behind the ­National Center for Complementary and ­Alternative Medicine in the US, last year ­confessed that he was ­disappointed with the organisation he helped ­establish because "one of the purposes of this centre was to investigate and validate alternative approaches. Quite frankly, I must say publicly that it has fallen short." Instead the NCCAM has been "disproving things rather than seeking out and approving things".

So back to what we'll call "Me and My Overdose". On the count of 10 we all knocked back bottles of ­homeopathic remedies. In fact, we all overdosed five times for the sake of the ­newspaper ­photographers present and still ­remained unaffected. But there was a good reason for that, claimed the two homeopaths who turned up to watch proceedings: it's not the amount you take, it's how long you take it for ­(making me wonder if this is just the length of time it takes for an illness to ease on its own); and second, it didn't work ­because it wasn't prescribed to us ­(making me wonder if it only works if someone has told you it will). They also wheeled out – twice – the ­alleged fact that there are "400,000 ­homeopathic doctors in India", as though the proof was not so much in the pudding, but in there being a chef in the kitchen in the first place.

So in the name of science, I ­conducted an experiment. That night, I took a sleeping pill. I hadn't been ­prescribed it, so presumably it shouldn't work. But guess what? I went to sleep! I pondered the wisdom of ­taking the whole bottle to see if this would make no difference to the result – as was the case with my bottle of arnica – but by then I was too tired to follow through. Anyway, I'd already taken one overdose that day.