The current study aimed to assess the anticancer effects of the ethanolic extract of Ulva lactuca (Seaweeds) on Caco-2 cell line. U. lactuca, a natural source of poly-unsaturated fatty acids, may be inhibit cancerous cells proliferation through apoptosis and cell death. The MTT experiment revealed that U. lactuca's toxicity on Caco-2 cells was concentration-dependent. As the extract concentration reached 0.45 µg, the percentage of cell viability propagated to 100%, and when it reached 250 µg, it decreased to 14.7%. Ulva lactuca extract was found to have anti-proliferative activity against Caco-2 cancer cell line, with an IC50 of 17.33 µg/mL. After being exposed to U. lactuca, Caco-2 cells underwent cell cycle analysis, which revealed significant DNA accumulation in the S-Phase but not significantly in the G2-M and G0/G1 phases. Apoptosis was confirmed via oxidative activity supported apoptotic potential recording a significantly increased ROS, MDA levels. Here, we used comet assay to examine U. lactuca's potential for genotoxicity. When the IC 50 of U lactuca was utilized, it induces significant amount of DNA damage to Caco-2 cells. Using the alkaline single cell gel electrophoresis assay, the amount of DNA damage (tail DNA) and the length of DNA migration (comet) were both determined in both control and treated cells.