Abstract: OBJECTIVE To study the toxicity variation of Gelsemium elegans Benth. combined with Mussaenda pubescens. METHODS The U₇^*(7⁴) uniform design method was used by two factors and seven levels to investigate the toxicity changes with the death of mice as index in different groups of Gelsemium elegans Benth. combined with Mussaenda pubescens. Then LD₅₀ of Gelsemium elegans Benth. combined with Mussaenda pubescens were determinated. RESULTS The multivariate function model of uniform design was statistically significant(P<0.05). The best ratio of Gelsemium elegans Benth. combined with Mussaenda pubescens was 0.54∶14.23 by partial derivative. The dose ratio range from 1∶22 to 1∶36 by 3D surface analysis. The LD₅₀ of Gelsemium elegans Benth. was 0.32 g·kg^-1, and the LD50 was of Gelsemium elegans Benth combined with Mussaenda pubescens was 0.68 g·kg^-1. The toxicity was greatly reduced. CONCLUSION The toxicity of Gelsemium elegans Benth. combined with Mussaenda pubescens reduce. The results offer scientific basis for reasonable usage.