Hypertension (HTN) is the medical term for high blood pressure. It is dangerous because it makes the heart work too hard and contributes to atherosclerosis. Sep 30, Natural remedies to lower blood pressure include black cumin seeds, hawthorn extract, celery seeds, garlic, flaxseed, cardamom, and more. Apr 25, Along with dietary and lifestyle changes, you might decide to try herbs to help reduce your blood pressure. Some herbs may cause side effects.