1. The ability of the n-3 fatty acids in fish oil to lower blood pressure has been established. Dietary fish oil supplementation is effective in mild hypertension and, in certain cases, as an adjunct therapy in drug-treated hypertension. Efficacy may be enhanced by restricting sodium intake. 2. The overall benefit of fish oil in hypertension, however, has not yet been fully evaluated. We still need further information on the relative efficacy of individual omega-3 fatty acids and on additional cardiovascular benefits and possible disadvantages of increasing their consumption.