Antioxidative effect of ethanolic extracts of various tea materials(Camellia sinensis, Cassia tora, Lyc ium chinense, Polygonatum odoratum, Schizandrae chinensis) on red pepper seed oil was investigated. Ethanolic extracts were added to red pepper seed oil at a concentration of 0.05%(w/v). Two experimental conditions were employed : 50$pm$0.1oC for 45 days and 150$pm$3oC for 24 hours. Oxidation of red pepper seed oil was determined by measuring peroxide value and acid value. Electron donating ability(EDA) and total phenolic contents of each extract were also determined. The result showed that the extracts possess an antioxidative activities. The effectiveness of them was in the following order: C. sinensis>C. tora>P. odoratum>S. chinensis >L. chinense. Ethanolic extracts of C. sinensis showed substantially higher EDA value and total phenol contents than other tea materials. These results indicate that the antioxidative effect was strongly related with EDA and total phenol contents.