Currently, little is known about how the dosage of one component of traditional Chinese medicine (TCM) alters the pharmacokinetic properties of the others in prescriptions. Banxia-Xiexin Decoction (BXD) consists of concentrated granules of seven Chinese herbs. The aim of this study was to explore how dosage variations of Pinellia ternata (Thunb.) Breit., the monarch herb in BXD, affected the pharmacokinetics of baicalin (BAL) and ginsenoside Re (GsRe) in the blood of treated mice. The decoctions containing low dose, middle dose, and high dose of Pinellia ternata were administered orally to mice, and indirect competitive enzyme-linked immunosorbent assays (icELISAs) using an anti-BAL-monoclonal antibody (MAb) and anti-GsRe-MAb were performed to determine the concentrations of BAL and GsRe in the blood of treated mice. The results showed that variations of Pinellia ternata doses altered the contents of BAL and GsRe in mouse blood. In all the groups, the BAL concentrations peaked at approximately 30 min and again at approximately 400 min, while GsRe showed more concentration peaks than BAL. The AUC 0Àt of BAL showed a linear relationship with the dose of Pinellia ternata, and the AUC 0Àt of GsRe also showed a direct relationship with the dose of Pinellia ternata. IcELISA may represent a feasible method for the study of the pharmacokinetics of TCM. Moreover, these results provide a meaningful basis for evaluation of the interactions between the components in a complex prescription on their pharmacokinetics.