The native species Cordia lutea, is used in Peru by folk medicine in the treatment of liver diseases such as jaundice and others. From fluid extract of the flowers, flavonoidquercetin-3-O-rhamnoglucoside (rutin) was isolated and identified. The relative purity was assay by HPLC and structural elucidation using 1H and 13C NMR spectral data in comparison with literature. Quercetin-3-O-rhamnoglucoside (rutin), was the major component of the fluid extract obtained from C. lutea flowers, with a relative purity, after crystallization, of 97.55% and 8% yield from the extract. As a conclusion for this investigation, it is important to note, that with the fluid extract from the flowers of C. lutea it is possible the isolation of the flavonoidquercetin-3-O-rhamno glucoside (rutin) with high purity and yield. This compound was not previously described in the flowers of this plant species.