Buying Health

After reading about the history of bloodletting, Yglesias wonders about our ability to tell medicine from snake oil:

I think discussions of health care economics pay far too little attention to the question of pre-modern health care. People have been earning a living as medical professionals for a long time. And yet everybody knows that the invention of actually useful medical treatments is pretty recent development. Surely this tells us something about the nature of the health care consumer’s ability to find and purchase cost effective treatments.