From the Associated Press:
About half of American doctors in a new study regularly give their patients placebo pills without telling them.
or
About half of American doctors in a new survey say they regularly give patients placebo treatments — usually drugs or vitamins that won't really help their condition. And many of these doctors are not honest with their patients about what they are doing, the survey found.
Call me silly, but if the patient were to be told that she'd been given a placebo, wouldn't it as-if-by-magic cease to be a placebo?