Just to explain the terms "double blind" for those that aren't...

Just to explain the terms "double blind" for those that aren't familiar with clinical trials:

A single blind study is where the patients know what they are taking (eg the placebo is in a differnt form or colour than the trial drug) but the investigators analysing the results are "blinded" to what individual participants are taking.

A double blind study is where neither participants nor investigators know whether they are taking active or trial drug, until the code is broken at the end of the study. This is the most reliable form of drug trial, as the result cannot be influenced (biased) by people's beliefs.
(There is also a "triple blind" study - where the investigators lose the code so no-one knows what anyone was taking!)

Go ANP!