A double-blind clinical study was carried out on subjects with Japanese cedar pollinosis for the evaluation of the effects and safety of ‘Benifuuki’ green tea, which contains epigallocatechin-3-O-(3-O-methyl)-gallate (O-methylated catechin), and a combination of ‘Benifuuki’ green tea and ginger extract, with ‘Yabukita’ green tea as a placebo. First, the effect of the combination of ‘Benifuuki’ green tea and various vegetable extracts on cytokine production inhibition was investigated using mast cells ; the simultaneous use of ‘Benifuuki’ green tea and ginger extract was found to suppress cytokine (TNF-α or MIPI-α) production to a remarkable extent. Subjects were given 1.5 g of ‘Benifuuki’ green tea, ‘Benifuuki’ green tea containing 30 mg of ginger extract, or ‘Yabukita’ green tea with water twice every day for 13 weeks. As cedar pollen scattering increased, the severity of pollinosis symptoms among the groups was observed to increase in the following order : placebo group>’Benifuuki’ group>’Benifuuki’ and ginger group. Eleven weeks after the beginning of treatment, during the most severe cedar pollen scattering period, symptoms of runny nose and itchy eyes were significantly relieved among the ‘Benifuuki’ group compared with the placebo group (p<0.05). In the ‘Benifuuki’ and ginger group, runny nose, itchy eyes and nose symptom scores were significantly reduced at the eleventh week, and nasal congestion, sore throat and nose symptom medication scores were significantly reduced at the thirteenth week compared with the placebo group. Among all test groups, hematological examination, general biochemical examination, determination of total IgG, CMV antibody titer, and serum iron content, and interviews throughout the intake period found no changes related to clinical problems. These results suggest that intake of ‘Benifuuki’ green tea over one month is useful in reducing some of the symptoms of Japanese cedar pollinosis, and did not affect normal immune response in subjects with Japanese cedar-pollinosis. It was also found that the addition of ginger extract enhanced the effect of ‘Benifuuki’ green tea.