Phenanthroindolizidine alkaloids are a family of plant-derived compounds with significant antineoplastic activity as well as other effects like antiamebicidal, antiviral, and anti-inflammatory activities. The specific biomolecular targets of these compounds have not yet been clearly identified. S-(+)-Deoxytylophorinidine (CAT) is a new phenanthroindolizidine alkaloid, originally extracted from the roots of Tylophora atrofolliculata and Tylophora ovata. Potent anticancer activity was observed in vitro and in vivo. Neurotoxicity of CAT was also studied and it was far less serious than that of vinblastine. Interactions between this compound and DNA had been studied in detail in our laboratory previously, and we further studied its interactions with RNA.