AIM To investigated the protective effects of the extract of C.Songaricum against Aβ1-42 induced injury in vivo by determination of the learning and memory ability as well as expressions of activated cAMP response element binding protein by phosphoration (pCREB) and NGF.METHODS 40 SD rats were randomly divided into 4 groups : control, model and treatment groups with donepezil hydrochloride and extract with C.songarlcum by intragastric administration.The Alzheimers disease (AD) model was established by injection of agglomerated Aβ1-42 in rats hippocampus.After treating 28 d, the Y-maze was used to test the learning and memory ability, the histomorphological changes of neurons were observed by Nissls staining, immunohistochemistry and Western blotting were used to test the expression changes of pCREB and NGF.RESULTS The results of Y-maze showed the total reaction time and error number of the treatment group with C Songaricum [(23.5 ± 3.35) min, (10.1 ± 2.46) rain, respectively] were significantly lower than model group [(31.44 ±: 5.93) min, (16.11 ± 3.74) min].Histomorphological observation showed the neurons in CA1 region of hippocampal in model rats were obviously damaged, which were manifested by severely decrease of Nissl body and cytoplasm vacuolar degeneration, while this pathological changes could be proved after C.Songaricum treating.Immunobistochemistry and Westera blotting results showed the the extract of C.songaricum increased the expressions of pCREB and NGF comparing with the model group.CONCLUSION The extract of the C.songaricum might improve the learning and memory ability as well as neurons histomorphology in AD rats induced by Aβ1-42 partly dues to regulate the expression of pCREB and its downstream target NGF.