Objectives : For evaluation of preventive and anti-diabetic activities of Cinnamomi ramulus(CR) herbal acupuncture on pancreatic islet damage in streptozotocin(STZ)-induced diabetic rat. Methods : CR herbal acupuncture was performed at Bisu($BL_{20}$) for 3 weeks subcutaneously starting1 week before STZ i.p. injection. SD rats were divided into four groups(n=10 for each group); 1) NC group, non-treated normal control group, 2) STZ group, STZ administered control group, 3) CR125 group, CR(125mg/kg) + STZ administered group, and 4) CR250 group, CR(250mg/kg) + STZ administered group. Results : Both of CR250 and CR125 groups showed increase in insulin secretion and decrease in the level of serum triglyceride and non-esterified fatty acid in a dose-dependent manner compared to the STZ group. Only CR250 group showed decrease in the levels of glucose and total cholesterol compared to the STZ group. CR herbal acupuncture prevents $eta$-cell damage of pancreatic islet, showing round figure on the sections of the pancreas. In the pancreatic cells, expressions of iNOS, JNK-2, P-JNK-1/2 and ERK-1/2 were decreased compared to the STZ group. CR herbal acupuncture solution did not show any cytotoxicity by MTS assay and inhibited expressions of iNOS and COX-2 in the STZ-induced diabetic rats. Conclusions : Therefore, we suggest that CR herbal acupuncture may act as a prophylactic as well as a therapeutic modality for diabetes mellitus.