[Research progress on antidepressant effects of Sini San based on three progressive levels of "single herb, herb-pair, and complicated Chinese herbal formula"].

Depression is a kind of mental illness accompanied by complex etiology and pathogenesis in clinic. With the quickening pace of circadian rhythm and increase of life pressure in modern society, the incidence of depression is increasing year by year. Nowadays, some typical antidepressant Western medicines, such as selective serotonin re-uptake inhibitors (SSRI) and tricyclic antidepressants (TCA), have been used as the main therapeutic drugs in clinic. Unfortunately, administration of these drugs will result in severe adverse reactions, slow treatments, and low cure rates, thus obviously they can not be used for a long term. Sini San, which originated from Treatise on Febrile Diseases written by Zhang zhongjing, is a prescription widely applied in clinic for curing mental illness and also a basic Chinese herbal formula for modern treatment of depression. This article would review the research progress on antidepressant effects of Sini San based on single herbs of Bupleuri Radix and Paeoniae Radix Alba, herb-pair of Bupleuri Radix-Paeoniae Radix Alba, and formula of Sini San, providing directions and ideas for future research on complicated Chinese herbal formulae.