Pregnant Wistar rats were exposed to ethanol under chronic conditions using the gavage method to assess the complement activation and effects of oxidative stress on fetus lymphoid organs and liver. 'Ihe effects were monitored on both the 10th (G10) and the 30th (G30) day of the offspring of alcoholic mother rats. Maternal ethanol caused a significant decrease in the glutathione level, whereas malondialdehyde and carbonyl levels increased in the liver and lymphoid tissues. Na+ ,K+ -ATPase, glutathione peroxidase, glutathione reductase, superoxide dismutase, and catalase activities in these organs also decreased. Furthermore, complement C3 and C5 activities of G10 and G30 groups were significantly higher compared with those of the control group. In conclusion, the results demonstrated that alcohol was capable of triggering damage to the membranes of the liver and lymphoid tissues of G10 and G30 groups, and C3 and C5 contributed to the development of alcohol-induced fetal tissue injury.