A simple, "green" and colorimetric approach in differentiating various anions is presented. Acidified ethanolic extracts from flowers of Anthurium andreanum undergo color changes in the presence of HSO4-, CH3COO-, C6H5COO-, HCO3-, CO32-, HPO42- and PO43- anions in aqueous solutions. Anionic acid-base conjugate pairs such as HCO3- and CO32-, HSO4- and SO42-, and phosphates H2PO4-, HPO42-, and PO43- can also be discriminated from each other. Visible spectroscopic analysis indicates possible structural changes in pigments due to pH change of solution as a consequence of the basic property of anions.