The aim of the present investigation was to evaluate the clinical efficacy of Xiong-gui-tiao-xue-yin, a traditional Japanese herbal medicine, in stimulating lactation in the postpartum period. We enrolled 82 women who had a normal delivery in Osaka Medical College Hospital, and randomly assigned them to the following two groups: a group of 41 women who received Xiong-gui-tiao-xue-yin at a dose of 6.0 g/day (Group X), and a group of 41 women who received ergometrine (methylergometrine maleate) at a dose of 0.375 mg/day (Group E). Volume of lactation was determined daily until Day 6 postpartum. Plasma prolactin and oxytocin concentration were measured at Days 1 and 6 postpartum. The results showed that volume of lactation was significantly higher in Group X than in Group E at Days 4 ( p = 0.042), 5 ( p = 0.038), and 6 ( p = 0.046). Significant differences between Groups X and E were noted in plasma prolactin concentration at Days 1 (157.9 ± 78.2 ng/ml and 129.1 ± 64.8 ng/ml ; p = 0.037) and 6 (167.5 ± 95.4 ng/ml and 117.1 ± 53.6 ng/ml ; p = 0.0042) postpartum. On the other hand, at Day 1, oxytocin concentration was significantly higher in Group E than in Group X ( p = 0.0024). No adverse effects were observed in this study. The results of our study demonstrate the beneficial effects of Xiong-gui-tiao-xue-yin on lactation, with increase in prolactin level without increase in oxytocin level in the postpartum period. Therefore, Xiong-gui-tiao-xue-yin can be expected to improve lactation in women in the postpartum period. Further detailed bio-pharmacological studies and clinical trials to investigate the properties of this drug are warranted.
