Four new phenanthroindolizidine alkaloids, tylophoridicines C-F, together With three known ones, R-(+)-deoxytylophorinidine, tylophorinine and tylophorinidine, were isolated from the roots of Tylophora atrofolliculata. The structures were determined oil the basis of spectral evidence. These alkaloids exhibited cytotoxic activity in vitro on HCT-8 cell (with IC50 values in the range 0.083 to 18.99 muM) and KB cell (in the range 3.56 to 18.22 muM) lines.