<p>A selective optical fiber gallic acid (GA) sensor was developed by integrating a molecularly imprinted chitosan membrane with an optical fiber chemical sensor technique. The molecularly imprinted chitosan membrane coated onto surface of an optical fiber selectively extracts/concentrates GA into the membrane, while blocking out other substances in a sample solution from entering the membrane. GA extracted into the membrane was detected by passing a light beam through the optical fiber, and the intrinsic optical absorption signal by GA itself was detected as a sensing signal. This sensor achieved high sensitivity and selectivity because the molecularly imprinted membrane selectively concentrates analyte and blocks out interference species from sample matrices. The sensor achieved a detection limit of 23&#xa0;ng/mL. The sensor has been used for analyzing GA concentrations in red wine, red grape juice and plum juice. A standard addition/recovery test was also employed to verify the effectiveness of this sensor for analyzing GA in these samples, and the obtained recovery rate was between 83 and 107%.</p>