In the "Shang-Han-Lun", a famous old formulary in traditional Chinese medicine, the exogennous diseases are classified into six stages of syndromes according to the progress of the illness in general terms for tai-yang, shao-yang, yang-ming, tai-yin, shao-yin and jeu-yin stages. The frequency of particular combinations of two crude drugs used in the six stages of diseases was examined to obtain the guidance in the preparation of new and appropriate formulations for modern medical treatments. The best pairs frequently mentioned in the tai-yang and yang-ming stages were the pair of Glycyrrhizae Preparata Radix (Sha-kanzo in Japanese) and Cinnamomi Ramulus (Keishi in Japanese), and Rhei Rhizoma and Natrii Sulfas, respectively. The characteristic combinations in the shao-yang stage were the pairs containing Scutellariae Radix and Pinelliae Tuber, which is contained in te formulation Xiao-Chai-Hu-Tang (Sho-saiko-to in Japanese). The pair of Glycyrrhizae Preparata and Radix Paeoniae Radices is the characteristic in the tai-yin stage, which is used for the treatment of muscular spasms and pain. The pair of Aconiti Preparata and Zingiberis Rhizoma is used for the treatment of diarrhea with cold pain in the shao-yin and jue-jin stages. The present results of these crude drugs of pairings will be useful to create a new formulation of crude drugs for modern medical treatment.