Abstract: OBJECTIVE To provide reference for the prescriptions of Chinese patent medicine for vomit by exploring and analyzing the composition regularity of them. METHODS The prescriptions of Chinese patent medicine for vomit were collected from the New National Proprietary Chinese Medicine. The prescription information were extracted after strictly screened with inclusion and exclusion criteria. The prescriptions were imported into Excel 2010 to analysis the frequency of drug use. The Apriori template provided by SPSS Clementine 12.0 software was used for association rule analysis. SPSS (ver. 18.0) was adopted respectively for cluster analysis and factor analysis. Cluster analysis was carried out by Ochiai algorithm of binary variable data, one of the systematic clustering methods. And principal component analysis was used for factor analysis. RESULTS One hundred sixty six prescriptions of Chinese patent medicine were included in total. The frequency analysis showed that 40 drugs were used more than 15 times. The association rules analysis found out 21 association rules of medicine pairs, 19 association rules of medicine combination of 3 kinds of herbs and 8 association rules of medicine combination of 4 ingredients. Moreover, 8 medicine groups with relevance were extracted from the tree map generated by cluster analysis. In sum, 13 common factors were obtained from factor analysis, including 11 drug combinations. CONCLUSION Through frequency sorting, the effect of high frequency Chinese medicine was regulating qi and resolving damp. The association rules of medicine showed that Citri Reticulatae Pericarpiumd(Chenpi)→Magnoliae Officinalis Cortex(Houpo) and Citri Reticulatae Pericarpiumd (Chenpi)→Pinelliae Rhizomac(Banxia) reflected the therapy of qi-regulating with damp-resolving. Three and four medicine combinations were based on the formulation of Citri Reticulatae Pericarpiumd(Chenpi)→Magnoliae Officinalis Cortex(Houpo). On behalf of the therapy of qi-regulating with damp-resolving, Citri Reticulatae Pericarpiumd(Chenpi)→Pinelliae Rhizomac (Banxia) can participate in the composition of anti-vomiting Chinese patent medicine. The cluster analysis and factor analysis indicated that the treatment for vomiting is mainly based on the principle of qi-regulating with damp-resolving, supplemented by digestion.