A group of 50 spontaneously aborting women was compared with the same number of pregnant women whose pregnancies terminated uneventfully. Biochemical parameters were studied and particular attention was paid to the vitamin C and E levels in both groups. A significantly higher percentage of aborting women had individual values of serum alpha-tocopherol above the 0.50 mg/100 ml normal limit. There was no significant difference in overall frequency distribution of vitamin C values in both groups. However, at the end of the first trimester the mean values of vitamin C were significantly higher in the aborting group. This could not be interpreted as an evidence of causal association.