The great homeopathy debate has opened up once more.
A recent large-scale study by the Australian Health and Medical Research Council has shown that "there are no health conditions for which there is reliable evidence that homeopathy is effective".
The report found that people could risk their health if they reject established evidence-based medical treatments in favour of homeopathy.
This may be upsetting news for the people who have set up the world's most hilariously-named charity, Homeopaths without Borders, and indeed those it has 'treated'.
The science writer Ben Goldacre has excoriated homeopathy for years, based on numerous studies disproving it, but it seems many people prefer to trust the power of positive thinking.
A whole swathe of society is sceptical of science-based findings against homeopathy. They say studies are funded by Big Pharma, and that it's in the health industry's interests for us to remain sick.
Homeopathy was invented by Samuel Hahnemann, based on the principle that the more you dilute the effective ingredient, the more effective the ingredient becomes.
This has the interesting end result of producing tiny, expensive bottles of pure water, containing not one molecule of whatever ingredient is listed on the bottle.
Amid the debate about this report, I spoke to a man who had visited a homeopath with his then-two-year-old son, who has autism. Like most parents, he was willing to try anything to help his son, as long as it wouldn't do harm.
He was told that his son's autism was caused by the MMR vaccine (a claim from a now entirely discredited study), and that it could be "flushed out" in a year of homeopathic treatment.
It took a couple of weeks of twice-weekly visits to the homeopath, at €70 per session, before he realised blind hope and desperation had helped make a fool of him.
His son is four now. He still has autism. He will always have autism, and positive thinking can help him deal with it, but not cure it.
Positive thinking is worthwhile, but as a wise woman once showed me, you can't quench a candle just by thinking about it.
You have to blow as well. Think positively as much as you want, but trust in science.
- Deirdre O'Shaughnessy