OBJECTIVE: To explore the mechanism of diabetic encephalopathy and the effect of Chinese patent medicine Shenwu capsule on the cognitive function and apoptosis in ischemic-diabetic model rats. METHODS: The compound model of Wistar rats was duplicated with streptozotocin (STZ) injection (60 mg·kg -1) once intraperitoneally and transient occlusion of both carotid arteries. After 30 days treatment with Shenwu capsule of high, middle and low dosages, the ability of learning and memory function were tested by water maze. The expressions of apoptosis protein Bax, Bcl-2 and Caspase-3 were evaluated by Western blotting in rat hippocampus. RESULTS: After 4 consecutive days of training, the swimming time to platform in isehemic-diabetic compound model rats was 63.4% longer than that of control group (P < 0.05), that of Shenwu groups was shorter than model 61.3% and 75.3% for low and middle dosage respectively (P < 0.05). Western blot analysis revealed that the expression of Bax in the middle and high dosage reduced significantly compared with model rats; Bcl-2 protein expression was lower in the model group than that of controls, while that of the Shenwu groups were higher than model rats; Caspase-3 in the model group increased compared with controls, whereas those in the middle and high dosage reduced. CONCLUSION: On the basis of causing diabetes mellitus with STZ, executing transient occlusion of both carotid arteries built diabetic encephalopathy rat model effectively and quickly. The model rats had cognitive disfunction. Cell apoptosis in neurons is one of the factors of the mechanism of diaetic encephalopathy. Shenwu capsule improved the learning and memory function and inhibited apoptosis in rats.