This is from a small study which might turn out to be wrong, so take it with a grain of salt. (Or sugar.) But apparently the placebo effect might work even if patients know they're getting fake medicine:
Half the patients were given a bottle with the word "placebo" printed on it. The pills it held, they were told, were like sugar pills. The patients were told they didn't even need to believe in the placebo effect, but had to take the pills twice daily. The other half were given no treatment at all.
At the end of the three-week trial, 59% of the patients taking the placebo said their symptoms had been adequately relieved, far outstripping the 35% in the non-treatment group.
...."What seems to be the active ingredient is the warm, personal relationship," said Dr. Howard Brody of the University of Texas Medical Branch in Galveston.
Fascinating, no? Anyone want to take bets on whether this gets replicated in a larger study?