Figure 3: Classification of the 23 selected trials. The 4 single herb trials are marked at their upper-left corners, the 9 Chinese studies can be identified by the name of the first author in Chinese character. The 15 trials without Zheng differentiation were in boxes with single line and the 8 trials with Zheng differentiation were in italic. Boxes for trials with positive results are shaded. The fifteen trials applied placebo control marked with *. Others used positive comparators. Numbers in brackets are numbers of cases in CHM treatment/comparison groups.