The current study tested whether the spontaneously hypertensive rats (SHR) from Charles River Laboratories are resistant or not to NaCl-induced rises of blood pressure and stroke deaths. These rats are fairly NaCl-resistant on a 2.1% high K diet, whereas they are quite susceptible to NaCl-induced hypertension and stroke deaths on a 0.5% normal K diet. Thus, a high K diet strongly protects against an NaCl-induced rise of blood pressure as well as stroke deaths in these SHR rats. Hence the level of dietary K determines the degree of NaCl sensitivity in these SHR rats. Am J Hypertens 1990;3:482-484