Todd Seavey:

No one has ever observed or measured any Qi....Barring a huge upsurge in popular respect for science, technology, and mainstream medicine, the best hope for putting an end to bogus alternative medicine practices may be to unleash the trial lawyers who so plague mainstream doctors. If enough mainstream patients are lured into alternative medicine, sooner or later they're going to start noticing that the alternative healers aren't doing a thing for their Qi flow, not to mention their sprained ankles or bronchitis, and they aren't going to be happy about it.

Iain Murray also has something on the ignorance surrounding herbal medicines like ephedra (in the comments that's me failing to convince "Rick" that there's such a thing as science). And Pete Geddes makes some good points about risk:

I have many friends who, in an effort to avoid trace amounts of synthetic chemicals found on "regular" produce, eat only organic. Yet they rock climb, kayak, and ski the backcountry. These activities are far riskier than consuming chemical residues on food.

There is a persistent misconception that human exposure to synthetic chemicals is responsible for soaring cancer rates. This is simply not true....

Another misconception is that synthetic chemicals are more toxic than natural ones.

Yeah, we had friends over last night who were all gaga over organic. Yet I'm so bad at presenting the rational case that I just keep my mouth shut.