Tea (Camellia sinensis) is one of the most popularly consumed beverage worldwide. It is consumed mostly as green tea, oolong, or black tea. Black tea, good source of flavan-3-ols the theaflavins: mixture of theaflavin (TF), theaflavin-3-gallates, theaflavin-3′-gallates and theaflavin-3,3′-digallates, possess numerous biological and therapeutic properties. However, the exact mechanisms underlying these properties of TFs remain speculative. In the present study, we investigated the in vitro protective effect of theaflavin on membrane protein carbonyl group, sulfhydryl group (–SH) and erythrocyte hemolysis in rat. TFs (at micromolar concentration) showed significant antioxidant effect in protecting erythrocytes from oxidation-induced changes.