Objective: To explore cytotoxicity of Synsepalum dulcificum (S. dulcificum) Daniell (Sapotaceae) on human colon cancer (HCT-116 and HT-29), human monocytic leukemia (THP-1) and normal (HDFn) cell lines, and its effect on the expression of early apoptotic genes, c-fos and c-jun. Methods: Leaf, stem and berry of S. dulcificum were separately extracted by using 2 solvents, 10% ethanol (EtOH) and 80% methanol (MeOH). PrestoBlue® cell viability assay and qRT-PCR assay were conducted to examine the above objectives respectively. Results: Stem MeOH, stem EtOH, and berry EtOH extracts of S. dulcificum were cytotoxic to HCT-116 and HT-29 human colon cancer cells. For HCT-116, IC