Camptothecin (CPT), a cytotoxic quinoline alkaloid, is a potent DNA enzyme topoisomerase I (topo I) inhibitor with an IC50 and IC70 of 50 nM and 0.225 μM for breast cancer cell line MDA-MB-231. It has recently been undergoing phase I clinical trials. In 3D fluorescence spectra, Camptothecin presented 3 fluorescence peaks with excitation wavelengths lambdaex of 215, 255 and 365 nm, separately. Camptothecin shows high activity against various tumor cells.