When one thinks about placebos, sugar pills come to mind.
As Shadowfax illustrates, it’s can be so much more than that, ranging from IV fluids for flu-like symptoms to plain x-ray films for musculoskeletal pain.
A placebo can certainly be more vague than initially thought:
In the end, I don’t really know what a placebo is. There’s a no bright line that separates the “sham” treatments from the “real” ones, and consent is a variable which is inconstant in terms of patients’ ability or need to explicitly understand and agree to the treatments.
Most patients feel better when they see the doctor “doing something” for them, which is why so many unnecessary tests get done.