Dummy

The largest ever brain scan study of the placebo effect has revealed that it seems to act on systems in the brain that process the emotional aspects of pain, which could explain why sugar pills can ease discomfort.

Expectations, suggestion and social cues can all influence the placebo effect, where a person’s symptoms lessen after taking a dummy medicine that they believe to be an effective treatment. But how this affects the sensory pathways that transmit pain signals in the brain is unclear.
–New Scientist