“…The main components of Si-Ni-San are Radix Bupleuri Chinensis (Chaihu), Radix Paeoniae Alba (Shaoyao), Fructus Citri Aurantii (Zhishi), and Radix Glycyrrhizae Uralensi (Gancao), with saikosaponin, paeoniflorin, naringin and glycyrrhizin as major active ingredients (Yamamoto et al,1975;Takagi and Harada,1969;Rouseff et al, 1987;Nikitina, 1966). Among these ingredients, paeoniflorin has been widely investigated as an antioxidant, cognitive enhancer, endotheliumdependent vasodilator, and neuroprotective agent (Goto et al, 1996;Ryu et al, 2001;Tabata et al, 2001;Chen et al, 2006). However, the actual contribution of paeoniflorin in Si-Ni-San against contact dermatitis, a typical T cell-mediated DTH response, remains unclear.…”