The objective of this study was to examine whether the combination of n-3 polyunsaturated fatty acids PUFA) supplementation and physical exercise training would decrease oxidative stress in comparison with n-3 PUFA supplementation only in humans. Eighteen women college students were divided into a perilla oil supplemented control group or a perilla oil supplemented physical exercise trained group throughout the experimental period of 4 weeks. After the intervention in both groups, plasma triglyceride levels were decreased. Serum thiobarbituric acid reactive substances (TBARS) level in the control group was increased by n-3 PUFA supplementation. In the trained group, however, TBARS level was unchanged. Plasma vitamin C level in the trained group was significantly decreased by n-3 PUFA supplementation. These results suggest that the combination of n-3 PUFA supplementation and physical exercise training might result in attenuated tissue damage induced by reactive oxygen species, if appropriate daily antioxidants, especially vitamin C, were provided.