Homeopathy has been tested in hundreds of clinical trials since the mid-twentieth century, and the pattern that has emerged is consistent: larger, higher-quality, better-blinded trials tend to show smaller effects, and the largest, most careful comparisons find no effect beyond placebo. The most widely cited of these is a 2005 meta-analysis published in The Lancet by Aijing Shang and colleagues, which compared 110 placebo-controlled homeopathy trials against 110 matched conventional-medicine trials and concluded that homeopathy's apparent clinical effects were consistent with placebo once study quality and size were taken into account; the accompanying editorial was titled 'The End of Homoeopathy.' Homeopathy researchers have disputed the specific eight-trial subset the paper's headline conclusion rested on, but later independent reviews, including government evidence checks, reached substantively the same conclusion.
That conclusion has had direct regulatory consequences. The United Kingdom's House of Commons Science and Technology Committee published its own review, Evidence Check 2: Homeopathy, in February 2010, concluding that homeopathy works no better than placebo, that the National Health Service should stop funding it, and that its products should not be licensed as medicines able to carry treatment claims without evidence of efficacy. Homeopathy's remedies are generally not toxic in themselves, since almost none contain any detectable active ingredient, so the practice's main documented harm is indirect: cases where patients have used it in place of effective treatment for serious conditions, with the delay in real care causing preventable harm.