AIM: To observe platelet activation and fibrinolytic activity and evalute the effects of valsartan and amlodipine in elderly patients with essential hypertension. METHODS: Double antibody sandwich ELISA and spectrophotometric assay were used to examine the levels of platelet alpha granule membrane protein (GMP 140), tissue type plasminogen activator (t PA) and its inhibitor (PAI 1) in 57 elderly patients with essential hypertension and 30 normotensives. Valsartan was given in 29 cases (groupⅠ) and amlodipine in 28 cases (group Ⅱ) for 12 weeks. RESULTS: Elevated GMP 140, decreased t PA activity, and elevated PAI 1 activity were detected in the patients, but not in normotensives (P