One of the basic requirements of RCTs is to standardize every element of the intervention, with a view to ensuring that every subject in a trial receives the intervention with the same quality and quantity, therefore preventing bias in the evaluation of its efficacy and safety. While it is difficult, if not impossible, for us to trace how quality control was conducted in ancient clinical studies, the situation in current clinical studies in the form of RCTs is not reassuring. Results from our previous study showed that only one trial mentioned quality control of herbs in 167 RCTs.