The effects of maternal ethanol consumption for 4 weeks before and throughout gestation on polyamine content and diamine oxidase activity of maternal, embryonal and fetal tissues are reported. At the 12th day of pregnancy, a decrease of putrescine in the liver of the mother and marked increases in putrescine, cadaverine and spermidine in embryos were observed. At day 18, putrescine and cadaverine diminished in maternal liver and placenta, and no changes in amine content in fetal liver and brain were found. At day 12, diamine oxidase activity increased in maternal liver and placenta, whereas it greatly diminished in embryos. At day 18, enzyme activity decreased in maternal liver, placenta, fetal liver and brain. These results indicate that chronic ethanol ingestion induces alterations in polyamine concentrations and metabolism in growing and developing tissues during pregnancy that might contribute to the adverse effect of ethanol on conceptual development.