Genetically hypertensive rats receiving a high sodium content diet develop, within weeks of their birth, major alterations of tissues and blood vessels. The purpose of this study was to evaluate the effects of cicletanine, a synthetic antihypertensive drug, on the progress of genetic hypertension. Iffa Credo SHR-SP male rats aged 11 weeks were divided into 4 groups. One group was used as control and 3 groups were treated with oral cicletanine in doses of 10, 30 and 90 mg/kg/day respectively. The control group showed a high mortality rate due to a significant decrease of weight gain and a highly significant increase of blood pressure, these changes being associated with lesions of tissues and vessels in the brain, heart and kidneys. A curative treatment with cicletanine improved these parameters and was accompanied by good tissue preservation. The curative effect of cicletanine seems to be due to an increase in endogenous prostaglandin synthesis.