Two measurable indices of toxicity that can be correlated with exposure to propylene glycol dinitrate (PGDN) were evaluated along with its metabolism. Propylene glycol dinitrate was administered by rapid i.v. injection to male Fischer-344 rats. These rats demonstrated a dose-response of blood pressure (BP) to doses of PGDN ranging from 0.1 to 30 mg/kg; the maximum fall in systolic BP occurred within 1 min of dosing. The i.v. administration of PGDN to separate groups of animals resulted in an increase in cerebral blood flow that was correlated with the dose, but a clear dose-response was not obtained.