Abstract: AIM: To analyze pharmacodynamic interaction on diaphoretic effects among the components from Mao-to for finding an optimal combination.METHODS: According to the four components that included in Mao-to, an orthogonal design with 1-level = used and 0-level = not used, was selected in L₁₄(2⁴) and a mathematical model was built up with the nonlinear mixed effect model (NONMEM) for rat experiment. Vacuole incidence of axillary sweat gland was determined to evaluate the diaphoretic effect. The importance and effectiveness of each component were analyzed in combinations and the bias was evaluated by some charts.RESULTS: The prediction model showed that it would be Cassia Twig (B), Ephedra (A), Apricot (C), and Liquorice (D) in order by the importance and the best combination is A plus B, while the worst is C combined with D.CONCLUSION: Ephedra and Cassia Twig in combination have significant diaphoretic effect in rats, and the combination will show better effect in comparison with any single component.

Key words: Mao-to, Compound, Simulation, Pharmacodynamic interactions