Pseudocarps or seeds of Rosa multiflora, crude drug "Eijitsu" ( ?? ?? ), have been used as purgative in Japanese traditional medicine. R. wichuraiana was generally thought to be able to substitute for the plant. The n-butanol fractions of both plant seeds were tested on purgative activities with mice, and the values of the 50% effective dose (ED₅₀) were 5.6 g/kg as the seed weight for R. multiflora and 57 g/kg as the seed weight for R. wichuraiana. From pseudocarps of R. multiflora, a new purgative compound, multinoside A acetate, was isolated, and its ED₅₀ value was tested to be 150 mg/kg (77-291 mg/kg, 95% confidence limit). The other isolated compounds were three known quercetin glycsides, quercetin 3-O-xyloside, isoquercitrin and hyperin. From pseudocarps of R. wichuraiana, three quercetin glycosides, isoquercitrin, hyperin and quercetin 3-O-β-D-glucuronide were isolated similarly, but no purgative components of R. multiflora were detected.