Ginsenoside Rg1 (Rg1) is a pharmaceutically active component of ginseng, and is neuroprotective as reported. This experiment investigated whether Rg1 is effective on injury or apoptosis of Chinese hamster ovary (CHO) cells as induced by Abeta(25-35), or by excessive Abeta(1-42) and the mechanism involved. We used different Rg1 doses to pretreat CHO cells stably expressing APP751 and either wild-type PS1 (WT) or mutant PS1 (M146L) for 24h. Cell viability and apoptosis were examined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction assay, terminal deoxynucleotidyl-transferase-mediated dUTP transferase nick-end labeling (TUNEL), and fluorescent annexin V/propidium iodide (Annexin V-FITC/PI) staining. The expression of Abeta(1-42) and caspase-3 was investigated with immunofluorescent staining. Our results reveal that pretreatment with 25microM Rg1 can improve viability in cells injured by Abeta(25-35), inhibit the intracellular Abeta(1-42)-induced apoptosis in mutant PS1 M146L cells, and reduce the levels of Abeta(1-42) and active caspase-3. This study demonstrated that Rg1 can reduce the production of Abeta(1-42) and the activation of caspase-3, as a result, to attenuate the cell apoptosis.