Dried flower of Campsis grandiflora (Bignoniaceae), known as ryoushouka in Japanese, is a traditional Chinese medicine used to treat stagnant blood, contusion, pruritus, and gynecopathy such as menstrual and menopausal disorders. In the present study, we evaluated the stagnant blood flow (BF) improvement effect of the methanol extract (CG) of dried flowers of C. grandiflora using an in vivo assay, in a continuing effort to improve peripheral circulatory disturbance using natural sources. We used the assay system to monitor a decrease in BF in the tail vein microcirculation of mice subjected to sensitization with hen-egg white lysozyme. Bioassayguided fractionation of the CG led to the isolation of apigenin (1), acteoside (2), cleroindicin B (3), rengyol (4), and isorengyol (5). Apigenin (1) and acteoside (2) were identified as active compounds as they exhibited significant stagnant BF improvement effect in the peripheral circulation. This study proved the positive effect of ryoushouka against stagnant blood syndrome.