The prevalence of hypertension is high and increasing worldwide. Drug therapy is effective, but for both "prehypertensive" and treated hypertensive patients, lifestyle changes are also important. Dietary modification is a key part of these changes, although skepticism about the role of diet in determining blood pressure has slowed implementation of the available guidelines. However, there is now a large body of evidence supporting a role for dietary salt, potassium, alcohol, and body mass in determining blood pressure. Studies such as PREMIER have shown that salt restriction (<6 g/d), alcohol moderation (<2U/d in men and <1U/d in women), weight loss (if BMI>25), exercise, and a DASH (Dietary Approaches to Stop Hypertension) diet (supplying 20-30 mmol/d of potassium) can achieve decreases in systolic blood pressure of approximately 10 to 15 mm Hg when applied together. Of the dietary changes, salt intake remains the most amenable to change. But we must further reduce salt in processed food if it is to be part of a wider strategy to lower blood pressure in the general population. Nevertheless, the message to patients must be that dietary changes made within a concerted alteration in lifestyle can have a very significant impact on their blood pressure.