The kidney is one of the critical target organs for chronic cadmium toxicity. Cadmium is a cumulative nephrotoxicant, and preferentially accumulates and persists in the kidneys. The natriuretic and antidiuretic effects of methyl alcohol extracts of Chelidonium majus L. (C. majus) leaves were evaluated in kidney of cadmium-intoxicated rats. Ninety-six male Sprague-Dawley Albino rats were divided into two major groups (toxicity and biochemical, 60 and 36 rats, respectively). There was a decrease in kidney weight and serum electrolytes, but an increase in urinary volume, excretion of electrolytes, serum urea and creatinine, after 9 weeks of cadmium chloride intoxication. Treatment of C. majus methyl alcohol extract for 10 weeks starting 1 week before cadmium administration shifted the above parameters towards the normal values. These results were supported by molecular and histological investigations. Treatment with C. majus methyl alcohol extract has natriuretic and antidiuretic effects against cadmium-induced nephrotoxicity in rats.