Two types of herbal medicine, Toki-Shakuyaku-San (TSS) and Boui-Jiou-Tou (BJT), were considered from the view point of their possible preventive effect on senility using the Senescence-Accelerated Mouse (SAMP1TA/Ngs), which is thought to be a useful model of human aging. The investigation of the effects of TSS and BJT on the behavior, learning ability, longevity, and histological changes in animals may be important for basic studies on aging in humans. Pellet feed containing each herbal medicine was given to the treated group ad libitum for 24 weeks starting at the age of six weeks. Learning ability and the longevity of mice were assessed and spontaneous motor activity was also measured. Morphological examinations were performed. On the passive avoidance task, the period until acquisition of standard achievement rate was shorter in the treated groups than in the control groups. The mean number and the density of dendritic spines were higher in the BJT treated group than in the control group. With regard to life span, median survival time tended to be longer in the treated groups than in the control groups. The results of this study suggested that TSS and BJT have some valuable effect for the prevention of senility.