1. The effects of prolonged high sodium intake (duration 3 months) and meclofenamate were studied in two groups of male spontaneously hypertensive (SH) rats.
2. Group 1 (eight rats) received 1% NaCl in water and served as controls, and group 2 received 1% NaCl in water plus meclofenamate (3·5–4·0 mg daily).
3. Group 2 rats developed higher arterial pressure, renal vascular resistance and left ventricular weight and greater renal histological changes, with lower effective renal plasma flow, renal blood flow and glomerular filtration rate, than group 1. No differences were observed between the two groups in heart rate, body weight, fluid intake, urine volume, UNaV, UKV and right ventricular weight.
4. The results suggest that the combination of high sodium intake and meclofenamate exerts a greater damaging effect on the arterial pressure and renal function of SH rats than salt alone.