Effects of twenty-three aqueous herbal extracts used in oriental medicines on heme oxygenase (HO)-1 expression were estimated in a mouse hippocampal cell line, HT22. HO-1 is one of the cytoprotective enzymes activated various stimuli, and Western blot analysis was used for evaluated HO-1 expression. Six aqueous extracts such as Rhei Rhizoma, Paeoniae Radix, Uncariae Ramulus et Uncus, Theae Folium, Prunellae Spica, and Coptidis Rhizoma significantly increased HO-1 expression in HT22 cells at the concentration of 300 ${mu}$g/ml. In Addition, four aqueous extracts including Eucommiae Cortex, Moutan Cortex Radicis, Ginseng Radix Rubra, and Scutellariae Radix moderately increased HO-1 expression. These results would be usefulfor the isolation and identification of their neuroprotective principles.