OBJECTS: Sanjoin, the seeds of Zizyphus vulgaris var. spinosus has been used as the most important hypnotic agent in chinese medicine to treat insomnia. This research was performed in order to examine the effect of betulinic acid and sanjoinine-A which are components of Sanjoin. METHOD: Sleeping time, sleep recordings of EEG, serum serotonin level, and locomotor activity were measured in rats which received betulinic acid and sanjoinine-A as sleep induction material extracted from Sanjoin. RESULTS: 1) Groups received betulinic acid, sanjoinine-A, and lorazepam showed increased sleep time than control group with saline. 2) Groups with betulinic acid, sanjoinine-A, lorazepam and saline recorded beta-wave in sleep recording of EEG. In there was no significant difference among all groups. 3) No significant difference in serum serotonin level among all groups was found. 4) In autonomic activity testing, groups of betulinic acid, sanjoinine-A, and lorazepam showed significantly more decreased in activity than saline group. In comparison of groups of betulinic acid and sanjoinine-A with a group of lorazepam, there was no significant difference. CONCLUSION: These results suggests that betulinic acid and sanjoinine-A have the sedative effect like lorazepam rather than sleep effect.