To examine the effect of bamboo leaf flavonoids on isoflurane-induced neuronal apoptosis and cognitive impairment in aged rats. The primary hippocampal neurons were isolated and cultured. After hippocampal neurons were treated with 2% isoflurane for 6 h, and treated with 50, 80 and 100 mg/L of bamboo leaf flavonoids, the cell proliferation was measured by MTT method and cell apoptosis was measured by flow cytometry. The rats were inhaled with 1.4% isoflurane for 2 h, and injected intraperitoneally with 25, 50 and 100 mg/kg of bamboo leaf flavonoids for 5 consecutive days. The cognitive functions were examined by Morris water maze. The hippocampus were isolated for the determinations of Aβ_1-42, TNF-α and INF-γ by ELISA. Results showed that bamboo leaf flavonoids significantly increased the proliferation of hippocampal neurons and suppressed hippocampal neurons apoptosis compared with isoflurane treatment only. The result of Morris water maze showed that bamboo leaf flavonoids significantly decreased average escape latent period and increased the frequency of crossing platform. The results of ELISA showed that bamboo leaf flavonoids suppressed the expression of Aβ_1-42, TNF-α and INF-γ in hippocampus. Our findings suggested that bamboo leaf flavonoids enhanced immunity of aged rats and suppressed the expression of Aβ_1-42, leading to the inhibition of isoflurane-induced neuronal apoptosis and cognitive impairment.