Context:Chrozophora tinctoria (L.) A. Juss. (Euphorbiaceae) is known as ‘dyer’s-croton’ and used to obtain dye substances. Recently, natural antioxidants and colorants have been of interest because of their safety and therapeutic effects.Objective: This study investigates the antiproliferative and antioxidant activities of the various extracts and fractions from C. tinctoria and analyzes their phytochemical contents.Materials and methods: The aerial parts of C. tinctoria were extracted with water, ethyl acetate, n-butanol, and methanol/chloroform. Phenolic compounds and other constituents of the extracts were analyzed by HPLC/TOF-MS. The ethyl acetate extract (EA) was fractionated by flash chromatography. The extracts, fractions, and major phenolic compounds were investigated for their antiproliferative activities on human cervical adenocarcinoma (HeLa) cell line at the concentrations of 5–100 μg/mL by using BrdU ELISA assay during 24 h of incubation. DPPH radical scavenging activities (5–150 μg/mL) and total phenolic contents of the samples were also evaluated.Results: 4-Hydroxybenzoic acid (268.20 mg/kg), apigenin-7-glucoside (133.34 mg/kg), and gallic acid (68.92 mg/kg) were the major components of EA. CT/E-F6 (IC50 = 64.59 ± 0.01 μg/mL) exhibited the highest antiproliferative activity. CT/E-F2 (IC50= 14.0 ± 0.0 μg/mL) and some fractions displayed higher radical scavenging activity compared to synthetic antioxidant BHT (IC50 = 23.1 ± 0.0 μg/mL). Among the main phenolics, gallic acid exhibited the highest antiproliferative and radical scavenging abilities (IC50 < 5 μg/mL).Conclusion: In this study, we have determined the biologically active fractions and their high effects may be attributed to the presence of gallic acid.