text: BACKGROUND: Ginger is one of the most important spice crops and traditionally has been used as medicinal plant in Bangladesh. The present work is aimed to find out antioxidant and anticancer activities of two Bangladeshi ginger varieties (Fulbaria and Syedpuri) at young age grown under ambient (400  mol/mol) and elevated (800  mol/mol) CO2 concentrations against two human breast cancer cell lines (MCF-7 and MDA-MB-231). METHODS: The effects of ginger on MCF-7 and MDA-MB-231 cell lines were determined using TBA (thiobarbituric acid) and MTT [3-(4,5-dimethylthiazolyl)-2,5-diphenyl-tetrazolium bromide] assays. Reversed-phase HPLC was used to assay flavonoids composition among Fulbaria and Syedpuri ginger varieties grown under increasing CO2 concentration from 400 to 800  mol/mol. RESULTS: Antioxidant activities in both varieties found increased significantly (P  <= 0.05) with increasing CO2 concentration from 400 to 800  mol/mol. High antioxidant activities were observed in the rhizomes of Syedpuri grown under elevated CO2 concentration. The results showed that enriched ginger extract (rhizomes) exhibited the highest anticancer activity on MCF-7 cancer cells with IC50 values of 34.8 and 25.7  g/ml for Fulbaria and Syedpuri respectively. IC50 values for MDA-MB-231 exhibition were 32.53 and 30.20  g/ml for rhizomes extract of Fulbaria and Syedpuri accordingly. CONCLUSIONS: Fulbaria and Syedpuri possess antioxidant and anticancer properties especially when grown under elevated CO2 concentration. The use of ginger grown under elevated CO2 concentration may have potential in the treatment and prevention of cancer.