It's always slightly surprising to meet one of the many well-educated Germany who believe that homoepathic medicine works -- that is, that it has a physiological effect in addition to the placebo effect. It's like talking to a prim, proper middle-class couple for a while and then having them calmly announce to you they're into bondage. Homeopathy is mainstream in Germany, as in all continental European countries. You can find homeopathic 'remedies' in every German pharmacy. Sometimes they are advertised as homeopathic, sometimes this fact is relegated to the fine print, so that customers who understand that homoepathic remedies are placebos may nevertheless be gulled into buying them. German universities routinely offer courses in the history of homeopathy, and in 2008, the first German professor of homeopathy and alternative medicine was created (g).
Homeopathy is one of the more unexpected Anglo-Saxon / Continental European cultural markers. Not that there isn't homoepathy in the U.S. and the U.K. -- as James Randi points out in the above video, there are also homeopathic 'medicines' on sale in nationwide drugstore chains in America. But homeopathy is much more entrenched in Europe. Both France and German are home to large companies that manufacture homeopathic products, and the Swiss government, for instance, issued a report in 2011 finding that homeopathy was effective and should be covered by health insurance. The UK government, by contrast, issued a report at the same time finding that homeopathy is bunk, should not be covered by the NHS, and is unworthy of further research. Wikipedia informs us that homeopathy is in decline in the UK, with one homeopathic hospital closing in 2009 and another renaming itself. In the US, '[t]eaching of homeopathy in the USA declined rapidly in the 20th century' and only tiny percentages of Americans use it.
The Overton window is a useful framework. Homeopathy exists in Anglo-Saxon countries, but it's marginal and controversial, and there are active and public forces hostile to it, so it's not Unthinkable, but certainly Radical. In Europe, it still seems to be Sensible and Popular. And this seems unlikely to change.