Banxia Houpu Decoction, having been used for the treatment of depression-related diseases since ancient times, is a traditional Chinese medicinal empirical formula consisting of Pinellia ternata, Poria cocos, Magnolia officinalis, Perilla frutescens and Zingiber officinale. The effects of the total decoction extract and five fractions therefrom, were evaluated in mice by tail suspension and forced swimming tests. The total 90% ethanol extract of the decoction was shown to possess an antidepressant activity that was close to that of Prozac, an antidepressant agent being applied clinically. Furthermore, the active principles were desmonstrated to be mainly in the aqueous (Bx4) and lipophic (Bx5) parts of the decoction extract while the polyphenol fraction (Bx2) exhibited a moderate action.