Xiao yao wan and jia wei xiao yao wan are two of the most prescribed TCM formulas generally, in large part due to their broad effects of mental health and GI related issues. Technically they fall into the "regulate and harmonize the liver and spleen" category with jia wei xiao yao wan clearing more heat in TCM terms than the base formula. Both are well known to aid with issues such as depression, anxiety and the subject of this study premenstrual syndrome (PMS).
In their multi-center, placebo-controlled, multi-center study, the researchers found that Jia wei xiao yao wan may be "effective, safe and well-tolerated" as a treatment for PMS. Of the 211 participants, 67 patients were in the treatment group and they found that those treated had "significantly greater reduction in psychological/somatic symptoms" and the treatment "significantly reduced PMS symptoms in the luteal phase over 3 menstrual cycles in contrast to placebo".