The method was established study the influence of different herbal combination with Radix Aconiti in the traditional medical formulae on content of the aconite alkaloids, for elucidating the scientific basis of reducing the toxicity of aconite in traditional Chinese medical formulation. The samples for ESI-MS study were prepared by decocting a mixture of Radix Aconiti Lateralis Preparata ( RALP) with Radix Glycyrrhizae Preparata (RGP) , Radix Paeoniae Alba ( RPA) , Rhizoma Zingiberis (RZ) or Radix Et Rhizoma Rhei ( RERR) , separately, and extracting the residue of the above mentioned mixtures after decocting. The diester-diterpenoid alkaloids (DDAs) was lower in the herb couples of RALP-RGP, RALP-RPA, RALP-RZ and RALP-RERR, and lipo-alkaloids was increased in the herb couples of RALP-RGP, RALP-RPA and RALP-RZ. The reason of reducing toxic effect principle is that the components of RGP, RPA and RZ have ester-exchange reactions with DDAs in RALP to produce lipo-alkaloids of low toxicity in the decocting process of the herb couples. The combination of RALP-RERR can reduce the content of DDAs in decoction and residue due to the formation of water insoluble alkaloid compound.