Colon cancer is the third most prevalent type of cancer among men and the second among women, with a worldwide incidence of about 9%. Epidemiological data suggest that diet is a major factor in the etiology of colon cancer. The aim of this study was to evaluate the antioxidant activity (AA) and the influence of 3,4-dihydroxyphenylacetic (3,4-DHPAA), p-coumaric (p-CoA), vanillic (VA) and ferulic (FA) acids on cell viability, cell cycle progression and rate of apoptosis in human colon adenocarcinoma cells (HT-29). HT-29 cells were incubated with different concentrations (0.1 to 100 μM) of 3,4-DHPAA, p-CoA, VA and FA for 24 h. Cell viability was measured using MTT method , cell cycle and apoptosis by flow cytometry. The AA of phenolic acids was determined using DPPH, ORAC, ABTS and FRAP assays, where 3,4-DHPAA showed the highest AA, followed by VA, FA and p-CoA. 3,4-DHPAA (94%) showed the highest AA followed by VA (17%), FA (15%) and p-CoA (12%) in DDPH . The results showed that the phenolic compounds are able to reduce cell viability with an average 66% for 3,4-DHPAA, followed by FA (63%), p-CoA (40%) and for VA (23%). 3,4-DHPAA promoted an increase in the percentage of cells in G0/G1 phase, accompanied by a reduction of cells in G2 /M phase and promote cell cycle arrest in G0/G1 phase. Cell cycle analysis of VA and FA showed a decrease in the proportion of cells in G0/G1 phase (10 µM and 100 µM). Results also showed that FA decreased the percentage of viable cells and increased the percentage of apoptotic cells (10 µM) and non-apoptotic cells as well as VA (100µM). Our results showed that phenolic acids presented high AA and cytotoxic effect in human colon adenocarcinoma cells, being 3,4-DHPAA more highlighted because reduced cell viability and promoted cell cycle arrest.