A blood pressure-lowering effect of increased prostaglandin synthesis via polyunsaturated fatty acids has been demonstrated in animal experiments. To our knowledge, for the first time an attempt was made to lower elevated blood pressures in adolescents (age 15-18 years) through a diet enriched in polyunsaturated fatty acids. This community-based dietary trial involved 30 students in the diet group and 20 students in the control group without any dietary intervention. Within 6 weeks the systolic blood pressure decreased by almost 11 mm Hg in the diet group and by 6 mm Hg in the control group. Diastolic blood pressure fell by 2 and 1 mm Hg, respectively. The effect on blood pressure was markedly different in normal weight adolescents. Systolic blood pressure in the diet group decreased by 14 mm Hg but only by 5 mm Hg in the control group. Diastolic blood pressure levels fell by 4 mm Hg in the diet group and increased by 4 mm Hg in the control group. Unfortunately, the numbers in these two comparison groups were rather small. The majority (70%) of adolescents with high blood pressure was overweight (greater than or equal to 20% above normal weight). However, for the small group of normal weight adolescents, the diet enriched with polyunsaturated fatty acids may be suitable to reduce elevated blood pressure levels.