Abstract: ObjectiveTotal alkaloids contents and acute toxicity of Herba Leonuri were researched to probe the influence caused by different combinations. MethodsUV spectrophotometry was used to measure the content of total alkaloids and the classical method of acute toxicity was used to compare the difference of acute toxicity among different combinations. ResultsThe contents of total alkaloids in the samples of Herba Leonuri, Herba Leonuri + Angelica sinensis, Herba Leonuri+ Ligusticum chuanxiong, Herba Leonuri + Aucklandia lappa and the whole formula were separately 0.51%, 0.34%, 0.37%, 0.37%, 0.36%. Calculated by crude drug content of Herba Leonuri, the MTD of Herba Leonuri was 2.34 g·kg-1 and the MLD of other for samples were respectively 3.52, 3.23, 3.60, 3.32 g·kg-1, which were respectively equal to 218.8, 328.8, 301.6, 336.3, 310.0 times of 70 kg person's daily dried medicinal herb expenses. Making continuous observation of 14 days, mice were generally in good condition and only two mice in the group of Herba Leonuri were dead. ConclusionThe content of total alkaloids and the acute toxicity of Herba Leonuri are closely related to compatibilities. The MTD shows the basic security and low toxicity of Herba Leonuri. The combination of Angelica sinensis, Ligusticum chuanxiong or Aucklandia lappa with Herba Leonuri can reduce toxicity via reducing the content of total alkaloids in Herba Leonuri.

Key words: Herba Leonuri, compatibility, total alkaloids, acute toxicity