“Robert Ader, a research psychologist at the University of Rochester, was engaged in an experiment in which he was trying to condition rats to dislike saccharin-sweetened water. This was similar to the classic experiment of Pavlov in which he conditioned dogs to salivate at the sound of a bell. In order to develop an aversion to the saccharin, Dr. Ader injected the rats with a chemical that made them nauseated so that they associated the sweet water with nausea. What he didn't realize until later was that the chemical be injected, cyclophosphamide, also suppressed the rats immune systems, so that they were dying mysteriously. But the striking thing was that now all he had to do was feed the rats saccharin-sweetened water and their immune systems would be suppressed, even though they had not been injected with the chemical, because they had learned (been conditioned) to associate the sweet water with the nausea-producing chemical. Now, simply feeding saccharin could produce suppression of the immune system. This was a landmark discovery, for it demonstrated that a brain phenomenon, in this case aversion to a taste, could control the immune system. (page 183)” PsychologyHealthConditioningPlacebo Book:Healing Back Pain Source: Healing Back Pain