AbstractThe effects of caffeic acid analogues isolated from Salviae Miltiorrhizae Radix were examined in rats with adenine‐induced renal failure and hypertension. Systolic, mean and diastolic blood pressures were decreased after magnesium lithospermate B administration. Oral administration of lithospermic acid B also decreased these blood pressure values even though the effects were weaker than those of magnesium lithospermate B. However, rats given lithospermic acid, rosmarinic acid or caffeic acid showed no appreciable changes in systolic, mean or diastolic blood pressure throughout the experimental period. Urinary excretion of both kallikrein and sodium was increased significantly in rats given magnesium lithospermate B or lithospermic acid B. These results indicate that the action of these compounds shows a structure‐specific patt