The Syst-Eur trial is a multicentre, randomized, double-blind, placebo controlled therapeutical trial in patients at least 60 years old and with isolated systolic hypertension. Its scope is to investigate the effects of modern antihypertensive drug treatment on morbidity and mortality and to assess possible adverse effects of the drugs used. Patients were recruited in 22 countries in western and eastern Europe and Israel. At three run-in visits 1 month apart their sitting systolic blood pressure (SBP) on single-blind placebo treatment averaged 180-219 mm Hg with diastolic blood pressure (DBP) lower than 95 mm Hg. After stratification for sex and the presence of cardiovascular complications, the patients were randomized either to active treatment or placebo. Active treatment consisted of nitrendipine (10-40 mg/day) with the possible addition of enalapril (5-20 mg/day) and/or hydrochlorothiazide (12.5-25 mg/day), titrated or combined to reduce the sitting SBP by at least 20 mm Hg to below 150 mm Hg. Matching placebos were employed similarly. The present progress report is based on the data received at the Coordinating Office before 1 March 1996. At that time 3433 subjects had been randomized. A total of 2015 patients had been followed for at least 1 year on double-blind treatment and 1298 patients for at least 2 years. At baseline BP was similar in both treatment groups and averaged 174/86 mm Hg. According to a per-protocol analysis at 1 year, BP fell (P < 0.001) on average by 22.6 +/- 15.7/6.0 +/- 8.0 mm Hg in the active treatment group and by 12.2 +/- 15.9/1.7 +/- 7.3 mm Hg in the placebo group. At 2 years BP was 10.2/5.7 mm Hg lower (P < 0.001) on active treatment than on placebo. At 1 year the percentage of patients who had reached goal BP was 19.9% in the placebo group and 41.4% in the active treatment group. At 2 years these percentages were 20.9 and 43.2 respectively.