In the present paper, we overview the discovery of new biological activities induced by ginsenoside Rg1 and Rb1 and discuss possible mechanisms of action. Both compounds could increase neural plasticity in efficacy and structure; especially Rg1, as one small molecular drug, can increase proliferation and differentiation of neural progenitor cells in dentate gyrus of hippocampus of normal adult mice and global ischemia model in gerbils. This finding has great value for treatment of Alzheimer's disease and other neurodegenerative disorders which is characterized by neurons loss. Increase of expression of brain derived neurotrophic factor, Bcl-2 and antioxidant enzyme, enhanced new synapse formation, inhibition of apoptosis and calcium overload are also important neuron protective factors. Rg1 and Rb1 have common effects, but there are some differences in pharmacology and mechanism. These differences may attribute to their different chemical structure. Rg1 is panaxtriol with two sugars, while Rb1 is panaxtriol with four sugars.