Objective: To study the rationality of combination prescription of Pearl Dropping Pills. Method: The pharmacodynamic study on healing of oral ulcerative macous membrane in rats was used as evaluation index. The interaction and variance analysis of orthogonal design were employed to explore the primary-secondary and correlation of all herbs in combination prescription. The orthogonal t-value experiment was adopted to research the proportion of prescription. Result: The importance of each herb in combination prescription of Pearl Dropping Pills was appeared to be:herba Inulae cappae>licorice> borneol> pearl. The obvious interactions between borneol and pearl and the synergistic effect of four herbs had been found to exist. The proportion of herba Inulae cappae

licorice

borneol and pearl were 100 ∶20 ∶2 ∶1. Conclusion: The combination of Pearl Dropping Pills is established and the rationality of the folk medicine is verified by this experimental study.