The effect of polyphenol concentration on the absorption of NO(2) into aqueous polyphenol solution was experimentally investigated. A gas mixture containing nitrogen dioxide was passed through a bubble-column-type batch-absorption apparatus, and concentrations of nitrite and nitrate in the absorbing liquid were measured. Aqueous polyphenol solution allows selective production of nitrite and inhibits the production of nitrate. The formation behavior of nitrite when this solution was used differed from that when aqueous sulfite solution or aqueous ascorbic acid solution was used.