This study has been undertaken to increase availability of native camellia in Jeonnam as a medicinal resource and to isolate the effective components from them. Fresh leaf and flower of camellia, single camellia tea and camellia tea mixed with green tea, herbs were screened for cytotoxicity on MCF -7 (human breast adenocarcinoma pleual effusion), Calu-6 (human pulmonary carcinoma), SNU-601 (human gastric carcinoma) cells. Also their multidrug-resistance reversing activity were evaluated using drug sensitive AML-2/WT and multidrug-resistant AML-2/D100 cells. Among the camellia extracts, young leaf and camellia tea mixed with green tea had strong growth inhibitory effects in below 100 $mu extrm{g}$/mL against human cancer cells. In result, young leaf showed the strongest inhibitory effects on MCF -7 ($IC_{50}$/ = 100 $mu extrm{g}$/mL ↑), Calu-6 ($IC_{50}$/ = 79 $mu extrm{g}$/mL), and SNU -601 ($IC_{50}$/ = 39 $mu extrm{g}$/mL), and AML-2/WT ($IC_{50}$/ = 64 $mu extrm{g}$/mL). Chemosensitizing effect was the extracts of mature leaf ($IC_{50}$/ = 97 $mu extrm{g}$/mL, RF=3.0), roasted tea ($IC_{50}$/ = 76 $mu extrm{g}$/mL, RF = 2.6 ↑) and steam tea ($IC_{50}$/ = 70 $mu extrm{g}$/mL, RF=2.8 ↑) strongly potentiate vincristine cytotoxicity in AML-2/D100 cells. But their cytotoxicities to both sensitive AML-2/WT and resistant AML-2/D100 cells were in the same order of magnitude. This results indicate that crude extracts of camellia mature leaves would contain some principles which have chemosensitizing activity.