Groups of up to 13 pregnant rats were individually caged. Body weight, food and water consumption were recorded at days 1, 8, 15 and 22 of gestation and the dams were treated on days 8-15 with sodium chlorite, 0.1%, 0.5% or 2% in drinking water or by injection of 10, 20, or 50 mg/kg IP or by gavaging with 200 mg/kg. To prevent ingestion of stillborn pups some dams were sacrificed at day 22. Other dams were allowed to deliver at term. Fetuses were weighed, measured and examined for soft tissue and skeletal malformations. Sodium chlorite, 20 or 50 mg/kg daily IP or gavaging with 200 mg/kg, caused vaginal and urethral bleeding. Doses of 10, 20 or 50 and 100% mortality of dams, respectively.