When Glasziou first started weighing the evidence for homeopathy, he writes, he had an open mind: "I had begun the journey with an "I don't know" attitude, curious about whether this unlikely treatment could ever work." But after considering 57 review studies that covered a total of 176 trials, he found no evidence that any of the experiments showed any positive results beyond the placebo effect. And while the placebo effect is certainly powerful enough in its own right, it can't stop the spread of infectious diseases like HIV or malaria. Delaying effective treatments in the hope that a homeopathic remedy will work is dangerous and risky, Glasziou writes.