Verapamil and nifedipine, two calcium-antagonist drugs, were evaluated in a double-blind cross-over trial. The study was performed in 15 patients admitted to our Coronary Care Unit for spontaneous angina. Before and after a 24 hours placebo period, oral verapamil 480 mg daily and oral nifedipine 60 mg daily were administered alternatively. Symptomatic as well as asymptomatic ischemic episodes with ST segment elevation or depression and ventricular and supraventricular ectopic beats were documented by continuous electrocardiographic Holter monitoring. The average number of attacks during the placebo periods was 243; the number of attacks decreased to 129 during verapamil treatment (P less than 0.05) and to 57 during nifedipine treatment (P less than 0.01). Ventricular ectopic beats decreased with both drugs while supraventricular ectopic beats decreased only during verapamil treatment. The difference was not statistically significant because of a small number of observations. In conclusion the two drugs appear to be effective in the management of patients with unstable angina at rest, especially in the variant form.