The aim of the present work was to study the activity of a new antihypertensive drug, a synthetic furopyridine, cicletanine, upon hypertensive morphological lesions of the retina. The stroke-prone spontaneously hypertensive rat strain (SHR-SP), known to develop hypertensive retinopathy, was a particularly suitable material in this view. The experiment was carried out in 39 rats (SHR-SP/A3N Iffa Credo), initially at the age of 11 weeks, divided into 3 groups: one as control group, the other two treated orally with 100 and 150 mg/kg cicletanine, respectively. All rats had free access to tap water containing 1% NaCl. For 46 days, blood pressure, body weight and death rate were recorded, then the rats were sacrificed. The eyes were removed, the posterior pole collected and fixed with Trump's liquid for transmission electron microscopy. In the control group, the capillaries showed marked hypertensive lesions. Multivesicular bodies were found in the different layers, particularly in the innermost layers; photoreceptor impairments could also be observed. In contrast to this group, both cicletanine-treated groups showed only rare and minimal lesions.