The aim of the study was to define a therapy to be combined with an immunosuppressive drug such as cyclosporin A, in order to partially reduce the nephrotoxic and hepatotoxic effects in the treated rats. Two drugs were considered: enalapril, which is an inhibitor of the angiotensin-converting enzyme, and spironolactone, which is an antagonist of aldosterone. These two drugs interrupt the renin-angiotensinogen-angiotensin chain after this has been activated by cyclosporin A, preventing peripheral vasoconstriction and more specifically the constriction of both glomerular arterioles and hepatic vessels from occurring, thus diminishing the cyclosporin A toxicity in both liver and kidney.