This paper aims to probe the effect of Rosa rugosa, Thunbergii which streptozotocin induced hyperglycemic rats was examined by glucose contents, body weight, kidney weight and histological observation. The results obtained were as follows: 1. The glucose level is decreased in the adminstered group of the Rosa rugosa compared with control group. These effects are in order named root group, stem group and leaf group group. BUN is increased fold of 1.52 in the control group compared with normal group, but the administered group of Rosa rugosa are decreased., in order named leaf group, root group and stem group. 2. The kidney hypertrophy to body weight is the higest in the control group compared with the other group in rats, and glucose contents are in order named stem group, leaf group and root group. 3. The loss of body weight is the highest in the control group, and the loss is in order named stem group, leaf group and root group in rats. 4. In histological observations, pancreatic pancreatic islets of control group shows disrupted or condensed nuclei, and the intercellular space between acini are enlarged. In the experimental group, histological damages of the acini and pancreatic islet are recovered compared with control group. Thes results suggest that the extracts of Rosa rugosa are effected to diabetes mellitus, root extract correlated with the function of kidney, and leaf extract is decreased plasma glucose.