Classical Chinese herbal therapy uses herb combinations within formulas based upon the belief that there is a synergistic effect between herbs. Herbal pairs and combinations may change the hydrophobicity and ion concentration of the decoction. These changes may increase extraction of constituents from other herbs within the formula. Furthermore, herbs may react within the decoction medium to create new chemical structures. The purpose of this study is to compare chemical signatures of individual Chinese herbs with paired herbal formulas, as they are used in Classical Chinese medicine.