Here’s what you need to know about cupping therapy: the International Olympic Committee allows it. That organisation prohibits steroids, meldonium and crack cocaine. It permits snake handling, prayer circles and aura reading.

I don’t suppose anybody has bothered to ask if the IOC has a problem with athletes smacking themselves in the face with knobbly sticks. Why would they? Such lunacy would generate bruises without leading to any concomitant improvement in performance. You know? Like cupping therapy. The practice is not physiotherapy; it is defined as an alternative medicine. So why hasn’t the IOC banned it? Because it doesn’t do anything. Were you not listening?

We have Michael Phelps – and friends on the US Olympic team – to thank for the unwelcome reappearance of this preposterous subject. Some folk who hadn’t been paying enough attention to Gwyneth Paltrow’s arms in 2004 were taken aback when the swimmer emerged from the pool decorated in blackened spots. His skin looked as if it were being prepared for a simplified game of Twister. The gymnast Alex Naddour was also in a dotty state. What on earth was going on?

In cupping therapy suction is applied to the skin using an apparatus that really does look like a cup. The air within is heated, and, as it cools and contracts, the skin is sucked into a disfiguring welt.

There is scarcely an ailment that does not, if well-paid practitioners are to be believed, yield to the persuasion of such ritual bruising. Muscle pain, acne, bronchitis, anaemia, infertility? You wonder why doctors bother going to medical school when, it seems, they could cure anything with a pint glass and a Bunsen burner.

Like witch-dunking and ritual incest, cupping has been around for centuries. Its origins can be traced to a variety of cultures throughout the ancient world. In the eyes of certain sentimentalists this means that it automatically has more worth than modern treatments devised by (shudder!) Men in White Coats working for (sinister organ chord!) Big Pharma.

European doctors used it until as late as the 19th century, but, like leeching, the practice vanished to be replaced by treatments that actually worked.

Much later, in our irrational century, Jennifer Aniston, Victoria Beckham and Michael Phelps took it up, and our collective intellectual centre of gravity shifted a few clicks back towards the Stone Age.

As is common with many such snake oils, the “science” part of the pseudoscience has mutated to fit the changing times. Traditional Chinese practitioners talk airily about the transference of energy from one part of the body to another.

This argument is sufficiently vague – is the energy heat, light, sound or electricity? – to defy any rigorous analysis. Now cup people talk about “encouraging the inflammatory responses of the body” to help athletes heal. Find the lady, find the lady! Can I interest you in buying the Brooklyn Bridge? I am a Nigerian prince and I need just $5,000 to help free up a lost fortune.

“There’s no science behind it whatsoever,” Dr David Colquhoun recently told the London Independent. “There’s some vague conceptual connection with acupuncture, and it is often sold by the same people. But how could it possibly do anything? It’s nonsense.”

What does he know? Yes, he may be professor of pharmacology at University College London, but I have a little man in Dublin 4 with a beard and an Enya CD who’ll cup away my gout for a four-figure sum.

I must, in an insincere attempt at balance, admit that, last week, I talked to somebody who swore that cupping worked wonders for back pain. They were keen to stress that, going into the session, they were highly sceptical and were won over by the hard results. There are arguments on both sides, and we must allow for flexibility in approaches to . . .

No, I’m not having that. There is, in the unstoppable growth of such gibberish, an embrace of the irrational that does a disservice to the scientists and philosophers who helped drag us out of the Dark Ages and towards the Enlightenment.

Obviously, people should be allowed to practice reiki, crystal healing, ozone therapy and (arguably the stupidest of all) homeopathy. We should also tolerate those who worship trees, drink their own urine and believe in the Westmeath panther.

But folk who sign up to such superstitions – and repudiate scientific methods – should not be allowed to watch telly, travel in aeroplanes or use the telephone. All such phenomenon are, after all, creations of the dreaded Men in White Coats.

Live in caves. Make your own loincloths. Eat mud and berries. Die before your 40th birthday from diseases against which you refuse to immunise. Are you happy now? Huh? Huh?