Proanthocyanidins (PCs) are numerous polyphenolic compounds found across a broad range of fruits, nuts, flowers, plant skins, and vegetables. Oxidative stress (OS) is the outcome of prooxidant accumulation, such as reactive oxygen species (ROS), beyond the cell's potential for antioxidants. Organelles may sustain damage by OS, macromolecules, and entire tissues. As a result, we employed a lung cancer mouse model caused by either a low or high dose of urethane/butylated hydroxytoluene to assess the antioxidant effectiveness of PCs. The results indicated that both doses of PACs were able to increase the malondialdehyde (MDA) levels while only the 50 mg/kg dose in G3 reduced the plasma superoxide dismutase (SOD) activity in treated mice, unlike the control group. However, both doses of PACs have elevated the catalase and glutathione reductase (GR) activities in G3 and G4 almost to control levels, particularly in G4.  Therefore, we concluded that PACs exert antioxidant activities in a way dependent on dosage and might serve as a natural adjuvant lung cancer treatment exerting antioxidant effect.