Chemotherapy frequently results in neurocognitive deficits that include impaired learning and memory. Thus, it is important to prevent or ameliorate the persistence of cognitive impairment. Compound K was employed to examine the ameliorating effect on chronic treatment with cyclophosphamide. Eight week-old ICR mice were given 80 mg/kg cyclophosphamide, cyclophosphamide combined with compound K (2.5, 5 and 10 mg/kg) or saline injections once per week for 4 weeks. Passive avoidance test and Y maze were used to evaluate memory and learning ability. Immunohistochemical staining for progenitor cell and immature neurons was used to assess changes in neurogenesis. Compound K ( 10 mg/kg) is able to ameliorate the decrease of neurogenesis in the hippocampus caused by cyclophosphamide. These results suggest that compound K might be a potential strategy to ameliorate or repair the disrupted hippocampal neurogenesis induced by the side effect of chemotherapy agent. (C) 2013 Elsevier Inc. All rights reserved.