Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity.Methods: Male Sprague–Dawley rats were divided into two groups: endocrine hypertension(HTN group) that received a combination of prednisone and salt for two weeks and oxidative stress-associated hypertension(HTN-OS group) that received additional induction of L-Nitro Arginine Methyl Esther(L-NAME) for two days. Each group was subdivided into 4 and treated intravenously with the extract 5; 10; and 20 mg/kg, and vehicle control. The systolic blood pressure(SBP), diastolic blood pressure(DBP), and mean arterial pressure(MAP) were recorded. The blood was taken before and at the end of recording for the measurement of serum concentration of nitric oxide(NO). The changes of blood pressure were analyzed by two-way ANOVA while its correlation with NO concentration was analyzed by Pearson’s Correlation.Results: The study showed a significant antihypertensive effect of the extract as compared with control group(P < 0.05) in both hypertensive models. Extract in the dose of 5 mg/kg showed the best blood pressure lowering effect. However, the correlation analysis did not show an association between NO increase and blood pressure lowering effect(P > 0.05).Conclusions: The study concludes that C. filiformis extract in the dose of 5 mg/kg exhibits the best blood pressure lowering effect in both animal models. Antihypertensive activity of the extract is not correlated with its antioxidant effect. Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity. Methods: Male Sprague-Dawley rats were divided into two groups: endocrine hypertension (HTN group) that received a combination of prednisone and salt for two weeks and oxidative stress-associated hypertension (HTN-OS group) that received additional induction of L-Nitro Arginine Methyl Esther (L-NAME) for two days. Each group was subdivided into 4 and treated intravenously with the extract The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded. The blood was taken before and at the end of recording for the measurement of serum concentration of nitric oxide (NO). The changes of blood pressure were analyzed by two-way ANOVA while its correlation with NO concentration was analyzed by Pearson’s Correlation. Results: The study showe The significant antihypertensive effect of the extract as compared with control group (P <0.05) in both hypertensive models. Extract in the dose of 5 mg / kg showed the best blood pressure lowering effect. However, the correlation analysis did not show an association between The increase in blood pressure lowering effect in both animal models. Anti-hypertensive activity of the extract is not correlated with its antioxidant effect.