The aim of this study was to examine the effect of crude bile on the human HepG2 and CCRF-CEM cell lines. Cells were exposed to different dilutions of bile. Antiproliferative effects were determined by the cytotoxic MTT assay. Cells undergoing apoptosis were identified by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Bile administration resulted in dose-dependent cytotoxicity in both HepG2 and CCRF-CEM cell lines. Incubated cells exhibited morphologic features of apoptosis. Bile has significant cytotoxic activity in HepG2 and CCRF-CEM cancer cells via induction of apoptosis. The mechanism of apoptosis needs to be further evaluated. It may have clinical utility in the treatment of cancer after in vivo confirmation of activity.