From a nice review of two books on the practice of medicine:

[The author] shows, for example, that people who take their placebos diligently do better than those who take them only occasionally; that placebo injections work better than placebo pills; that brand name placebos relieve pain better than generic placebos; and that blue placebos are better sedatives than red ones – except for Italian men, for whom the opposite is true.

Found at Arts & Letters Daily, of course.