An aunt who has never quite got over the passing of 1969 into 1970 recently told me that she was planning to take Charaka as prophylaxis for malaria on a trip to Botswana. Having picked the drug up in Switzerland from her homeopath, she wondered what I thought about it.

As with all homeopathic drugs, Charaka aims to aggravate the immune system into producing more of the same symptoms that the patient is already suffering. This, so the theory goes, will cure them of their disease. The "like cures like" premise was first established by Dr. Samuel Hahnemann in the late eighteenth century but Hahnemann also noticed that it wasn't such a good thing to have patients suffering twice as much as they were in the first place. To solve the problem he thought he would dilute his preparations. Dilution, he said, when done in the right way with the right amount of vigorous shaking at the right times would create a "memory" of the active molecule in the water molecules around it that would let the body know what it should do without inducing most of the actual symptoms themselves. Hahnemann recommended diluting active compounds 30 times at a ratio of one part of the tincture to 100 parts water each time.

To put this in context, if you start with 1ml of concentrated drug and put that whole volume through this dilution, you'll end up with enough finished product to fill a cube 1,000,000,000,000,000,000 metres per side. In other words, over 1 million light years cubed. Needless to say, in most homeopathic tinctures, not a single molecule of the original active ingredient remains.

In a report in The Guardian last week, it was revealed that over one fifth of NHS Hospital Trusts have cut or reduced funding to homeopathic services in the past two years. Such a change marks the first success for a campaign waged by many eminent scientists to end the practice altogether.

Why the NHS ever thought it necessary or acceptable to fund such a ridiculous practice is beyond many people. Whilst leeches, blood letting and popping arsenic have fallen by the wayside of their contemporary, the theory of homeopathy, has prevailed. What seems to sustain homeopathy today are three major factors. Firstly homeopathy does no harm – no one ever died from taking a little bit of water. It was just this ideal that Hahnemann was working towards when formulating his new type of treatment that would avoid the hideous side-effects of the medicines of his day. Side-effects still play an unfortunate role in today's medicine and many people want to ensure that they suffer from none of them – water is a very effective drug when a lack of side effects constitutes your measuring stick.

Perhaps the principal reason why reasonable people are not up in arms about homeopathy is the complete lack of appreciation amongst many members of the public for the difference between this sham and herbalism. Such a simple misunderstanding often allows homeopathy to escape scrutiny scot-free. Homeopathy is a pseudoscience based on the principles described above; herbalism is the use of traditional herbs such as St. John's Wort and Echinacea to treat common ailments. Whilst herbal pharmacies are not recommended by doctors as a first port of call for patients owing to the inability of herbal practitioners to assess symptoms in the context of more serious diseases that may be underlying them—the example of constipation as a symptom of bowel cancer is a good one—many herbal remedies have proven effectiveness. Indeed, many of today's drugs are based on the active extracts of these original medications.

The final reason for homeopathy's survival against all the odds is something that most medical practitioners in the twentieth century failed to recognise: it is the very human desire to think that, when all suggested conventional treatments have failed, there must be something else, some "natural" cure left that could solve the problem. This failure to understand patients as people and the consequent treatment of their ailments in isolation – rather than more modern holistic approaches – has been the major contributor to the whirlwind of cynicism and suspicion that is now being reaped by science.

But why come down so harshly on homeopathy? If alternative medicine is a human need, why not let it be? This is a common argument that often comes backed up with the assertion: "My aunt was really stressed and she took a homeopathic remedy and now she's fine." But whilst many complementary therapies are well placed to treat stress—massage, group therapy, reflexology, counselling, acupuncture, gym membership and many more—homeopathy is not. Because although your aunt might find that taking that ampoule of water to treat her stress removes the worst of the problem, she might then consult her pseudoscientific homeopath when she's planning a once-in-a-lifetime trip to Botswana.

She wouldn't go back to her acupuncture specialist for advice on malaria; she wouldn't refuse vaccines for her children based on what her gym manager told her and she wouldn't seek treatment from her group therapist for that constipation that has been bothering her for a while but which could actually be a sign of cancer.

For as many anecdotes that there are describing a homeopathic success story, there is another, more tragic tale of a young woman refusing surgery to remove an easily operable breast cancer, a cancer that would go on to kill her. This true story is told by Professor Michael Baum, Emeritus Professor of Surgery at University College, London and is one of the factors that led him to start his much needed campaign against what he calls the "hocus-pocus" of homeopathy. As Professor Baum points out, £5 million a year is spent on homeopathy by his NHS hospital trust alone, funding the Royal London Homeopathic Hospital. This would be more than enough to cover the cost of herceptin for the trust's breast cancer patients for example – a drug proven to be effective but which the NHS cannot currently afford to provide in all cases.

This waste of limited NHS resources is bad enough, but what is far worse is that for every day that passes with NHS funding seemingly substantiating the fraud of homeopathy, another person, confused by the complexity of conventional medicine or lacking the proper complementary care they need, may be heading to an early grave by sincerely seeking answers from charlatans.