There are several reports suggesting that Spirulina (Arthrospira) may have a beneficial effect in the prevention of cardiovascular diseases. Here we review the results of studies on the effects of dietary Spirulina on the vasomotor reactivity of aortic rings excised from either lean or obese Wistar rats. We also review preliminary results on the effects of Spirulina intake on plasma lipids and blood pressure in humans. The results of the former studies strongly suggest that Spirulina induces a tone-related increase in the synthesis/release of nitric oxide by the endothelium as well as an increase in the synthesis/release of a vasodilating cyclooxygenase-dependent metabolite of arachidonic acid and/or a decrease in the synthesis/release of a vasoconstricting eicosanoid by the endothelium. In humans, Spirulina maxima intake decreases blood pressure and plasma lipid concentrations, especially triacylglycerols and low-density lipoprotein-cholesterol, and indirectly modifies the total cholesterol and high-density lipoprotein-cholesterol values.