It has been shown by Dr. Hara that green tea catechins impede the action of ACE Inhibitors and supress the production of angiotensin II. Angiotensin II is the bad guy here. It is connected to hypertension and renal arterial stenosis. Dr. Hara's research indicates that daily consumption of green tea has the ability o prevent a rise in blood pressure.
I enjoy several cups of green tea daily. It has practically replaced the coffee I used to drink. I drink it for its many health benefits. It helps maintain healthy body weight by shifting metabolism to favor weight loss, improves cardiovascular health by reducing inflammation and improving blood vessel function, restricts a buildup of cholesterol, improves and maintains brain health. There are other benefits of drinking green tea I have not mentioned here.
One thing to watch for: people on anticoagulants (warfarin, Coumadin) should not drink too much green tea. It contains substantial amounts of vitamin K when taken in large amounts. Large amounts of green tea (.5 - 1 gallon or more) diminish the anticoagulants' effectiveness.