What would you say is the very best natural cure for high blood pressure?

None: There are no natural remedies. The best treatment can be recommended when the underlying cause can be identified. Weight loss, exercise, smoking cessation, reduced alcohol use , diet low in salt and rich in potassium are essential ways before meds are used.

DASH diet: Although not a cure, compliance with a low sodium dietary approaches to stop hypertension diet has been shown to be as effective as any single antihypertensive agent. The details of the diet can be found using any search engine. Additionally, exercise and weight loss as well as increased potassium intake may help to lower bp.