Placebos in clinical trials

Placebos were used in clinical trials in the 18th century to debunk "quack" cures. The so-called "non-quack" cures included bloodletting and feeding patients the undigested material from the intestines of an oriental goat. These needed no trials because they were considered to be so effective.

An example of how powerful placebos are is during the second world war. Supplies of morphine were running out, and a nurse was seen to inject a wounded soldier with saltwater instead of morphine before an operation. The soldier thought it was real morphine and didn't appear to feel any pain.