Recommendations to treat patients with mild hypertension are based principally on six randomized clinical trials conducted in three countries between 1964 and 1979. To determine whether the methods and results of these randomized clinical trials justify the current therapeutic policy, a clinical epidemiologic analysis of the data was performed focusing on (1) clinical versus statistical significance, (2) clinical heterogeneity of patients' baseline state, (3) suitable management of the untreated control patients, and (4) choice of outcome events. This analysis suggested that the results of available studies are better suited to public health decisions (number of cardiovascular deaths prevented nationwide) than personal health decisions (whether treatment does more good than harm for individual patients), and that current evidence does not justify a uniform policy of treating all asymptomatic patients with mild hypertension.