Increasing doses of nitrite (3.7-14.8 mg/kg BW) were administered via intragastric intubation to 64 spontaneously hypertensive Sprague-Dawley rats. Systemic blood pressure, measured in conscious animals with the tail cuff method, significantly decreased in a dose-related manner 16 and 32 minutes later, and pulse rate slightly increased. Since orally ingested nitrate may be partially converted to nitrite, it seems worthwhile to study correlations between dietary nitrate and blood pressure in experimental animals and man.