Objective: To assess the putative diuretic and antioxidant properties of Cassia occidentalis(C. occidentalis) leaves’ aqueous extract. Methods: Adult rats were administered with C. occidentalis leaves aqueous extract acutely(24-h) and subchronically(7 d), at doses 80, 160, 240, 320, and 400 mg/kg(per os). Negative control group received only an equivalent volume of distilled water, while the two positive control groups received the diuretic drugs furosemide(20 mg/kg, i.p.) and hydrochlorothiazide(HCTZ, 20 mg/kg, i.p.). Urinary elimination of electrolytes in response to treatments was evaluated, together with changes in concentrations of creatinine, urea, aldosterone, glucose, and albumin in urine and plasma. Various urinary indicators of kidney function and plasmatic markers of oxidative stress were also assessed. Results: The acute administration of C. occidentalis increased the urinary excretion of 107.58% at the higher dose tested, compared to negative control. The reference drugs furosemide and HCTZ induced increases of 84.27 % and 48.05 %, respectively. Acutely, the extract induced Na+ and Cl- elimination, whereas subchronically an increase in K+ elimination was also observed. The extract also improved the kidney function indexes and oxidative stress markers. These effects were dose-dependent and comparable with positive control observations. Conclusions: Our i ndings strongly suggest that C. occidentalis aqueous extract has diuretic and antioxidant activities, and deserves further studies considering the potential for the treatment of hypertension. Objective: To assess the putative diuretic and antioxidant properties of Cassia occidentalis (C. occidentalis) leaves’ aqueous extract. Methods: Adult rats were administered with C. occidentalis leaves aqueous extract acutely (24-h) and subchronically (7 d), at doses 80, 160, 240, 320, and 400 mg / kg (os os). Negative control group received only an equivalent volume of distilled water, while the two positive control groups received the diuretic furosemide (20 mg / kg, ip) and hydrochlorothiazide (HCTZ, 20 mg / kg, ip). Urinary elimination of electrolytes in response to measures was evaluated, together with changes in concentrations of creatinine, urea, aldosterone, glucose, and albumin in urine and plasma. function and plasmatic markers of oxidative stress were also assessed. Results: The acute administration of C. occidentalis increased the urinary excretion of 107.58% at the higher dose tested, compared to negative control. The reference drugs f Acutely, the extract induced Na + and Cl- elimination, while subchronically an increase in K + elimination was also observed. These extracts also improved the kidney function indexes and oxidative stress markers. These effects were dose-dependent and comparable with positive control observations. Conclusions: Our i ndsings strongly suggest that C. occidentalis aqueous extract has diuretic and antioxidant activities, and deserves further studies considering the potential for the treatment of hypertension.