1. Blood concentrations of ethylene and diethylene glycol were evaluated in Sprague-Dawley rats at varying intervals following oral dosages of the glycols. 2. Ethylene and diethylene glycol in rat blood stored under refrigeration at 4 degrees +/- 10 degrees C for a period of 30 days exhibited minimal concentration losses, contrary to previous reports. 3. The amount of oxalate in the blood and kidneys of Sprague-Dawley rats doses with ethylene and diethylene glycol was quantitated. The animals dosed with ethylene glycol demonstrated significantly higher oxalate levels, particularly at 8 hr post-dosing, than similar animals dosed with diethylene glycol. 4. Ethylene glycol induced oxalate deposition within the kidney without significant histologic changes. Diethylene glycol induced histologic changes within the kidneys without kidney oxalate deposition. 5. Maximal kidney oxalate levels, following ethylene glycol dosage, occurred concurrently with peak blood oxalate concentrations. In the case of diethylene glycol, kidney oxalate levels did not peak until 4 hr after maximal blood oxalate levels. 6. Ethylene and diethylene glycol induced different modes of death in Sprague-Dawley rats.