The Placebo effect
When testing a new medicine scientists have to conduct controlled tests to show that it is safe and effective. One factor they have to be very careful to control for is the placebo effect. The way that they do this is the randomised double-blind trial on a large sample of patients or volunteers. To find out more go to:-
A recent article from The Times newspaper
What causes the placebo effect?
Wikipedia article on the placebo effect
Bad Science on Radio 4 about the placebo effect