A "confidence interval" is a number used in statistics which provides the level of confidence that the results of the study are valid. In trying to find "evidence" that an orthodox treatment works, another statistical trick is to use a low confidence interval combined with a large number of studies. In other words, if you use a low confidence interval and fund a lot of studies, eventually one of the studies will give you a "statistically valid" study. But it is not because the product works, it is because of the nature of statistics and probability.