After a thorough evaluation of 57 scientific reviews that encompassed 176 studies on 68 illnesses, a panel of health experts has once again concluded that homeopathy is at best a placebo (when it's not being potentially harmful).

Homeopathy, which one of the panel members referred to as a “therapeutic dead-end,” is based on the idea that “like cures like” (a questionable proposition to start with). Thus, its practitioners claim that if you take a substance that causes a sickness or similar symptoms of a sickness, then dilute it—to the point where the result is plain water—you create a cure. There's no mechanism that can possibly explain this, but some tout the idea that water has memory that can retain therapeutic information after dilution has removed every last molecule of the “healing” substance.

These are centuries-old ideas, and we now know they defy basic knowledge of physics, chemistry, and biology. Accordingly, they've long been dismissed by the vast majority of modern scientists and physicians. All that hasn’t stopped homeopathy believers. In 2007, about 3.3 million Americans spent $2.9 billion on the industry. In the UK, the National Health Service picks up a $5.74 million (£4 million) check for two homeopathic hospitals and various water treatments.

The numbers, while puzzling, may appear harmless at first. People have the right to spend their money on what they wish, and there is no inherent danger in drinking a bit of water. But there is potential for homeopathy to injure patients, according to the expert panel, the Australian National Health and Medical Research Council (NHMRC).

“People who choose homeopathy may put their health at risk if they reject or delay treatments for which there is good evidence for safety and effectiveness,” the NHMRC concluded.

In a blog post, one of the NHMRC members, evidence-based medicine expert Paul Glasziou of Bond University, said he was “shocked” that homeopathic practitioners promote homeopathy treatments for infectious diseases like HIV/AIDS and malaria.

Perhaps what’s more shocking was Glasziou’s open-mindedness going into the review:

“I had begun the journey with an “I don’t know” attitude, curious about whether this unlikely treatment could ever work. Still, who would have believed that bacteria caused peptic ulcers, or that vaccines for cancers would become routine. So just maybe.…but I lost interest after looking at the 57 systematic reviews (on 68 conditions) which contained 176 individual studies and finding no discernible convincing effects beyond placebo.

To address skeptics who might point to some data in homeopathy's favor, Glasziou noted: