Herbs that have been clinically proven to moderate blood pressure include blond psyllium, garlic, basil and nela nelli, states the Pharmacognosy Review. Fifteen grams of blond psyllium daily lowers systolic pressure by about 8 millimeters of mercury and diastolic pressure by about 2 millimeters of mercury.
Garlic decreases blood pressure while it increases antioxidant vitamin C and E levels, notes the Pharmacognosy Review. Taking 30 milligram-per-kilogram doses of a basil extract results in decreased systolic, diastolic and average blood pressure; however, the effect lasts for two minutes. The extract contains eugenol, which acts as a calcium channel blocker.
Traditional medical practitioners use nela nelli to lower blood pressure and as a diuretic, explains Pharmacognosy Review. Clinical animal studies show that doses of a liquid extract from the plant produce a significant decrease in average diastolic, systolic and mean arterial pressures. The reductions in diastolic blood pressure readings were more significant than the reductions in the systolic readings.