High blood pressure is common in the population and is associated with an increased risk of vascular disease. This risk decreases already with a small reduction in blood pressure, even in people with blood pressure in the normal range. An updated Cochrane Review investigated the preventive effect of calcium intake on blood pressure. The results from 20 trials show that regular intake (median: 3.5 months) of 1-2 g calcium per day lowered systolic blood pressure by an average of 1.37 mmHg, regardless of age and sex. The effect is probably dose-dependent. Only one study investigated adverse effects, but found none. The overall confidence level of the evidence was high.