However, there has been little information regarding the phytochemicals composition and antioxidant activity of different parts of the gac fruit (mostly reported on fruit) in Thai cultivar. We collected gac fruits from three development stages, namely immature (green), mature (yellow) and ripe (red). Therefore, the purpose of this present study was to investigate the phytochemicals of different parts of the gac fruit and to evaluate the antioxidation activity by using DPPH radical-scavenging activity and ferric reducing/antioxidant power assay.