The study was designed to test the hypothesis whether cervical dysplasias of the more severe grades are associated with elevated erythrocyte glutathione levels. Subjects were women who obtained Pap tests and were subsequently found (1)not to have any cervical lesions or(2)to have colposcopically visualized, biopsy-confirmed cervical abnormalities histopathologically diagnosed as mild, moderate, severe dysplasias, or carcinoma in situ (CIS). The erythrocyte levels of reduced glutathione (GSH), oxidized glutathione (GSSG), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), and 6-phosphogluconate dehydrogenase (6PGD) were analyzed from coded peripheral venous blood samples. GSH and GR concentrations increased with increasing severity of dysplasia. Exploratory data analysis and multiple pairwise comparisons suggested comparable levels of the glutathione-related variables between these histopathological pairs'(1)mild and moderate dysplasias or(2) severe dysplasia and CIS. We suggest that the changes in erythrocyte glutathione-related indices in conjunction with histopathological diagnosis may have the potential to distinguish between low-and high-grade cervical dysplastic lesions.