32 patients in an early state of coronary sclerosis were investigated in connection with diagnostic angiography. 8 patients received 2 mg gallopamil (G) and for every 12 patients 0.1 mg/kg propranolol (P), respectively, 0.12 mg/kg Atenolol (A). All medications were injected intravenously over 4 min. The angiograms were repeated in identical projections before (control) as well as 5, 10, 15, and 20 min after G and 2, 4, 6...up to 20 min after P and A. All angiograms were analyzed using a quantitative computerized contour detection system. 10 min after infusion of G 34 measured coronary segments showed a significant (p less than 0.05) medium dilation of 21 +/- 4.3% and after a further 10 min an insignificant increase in coronary diameter was observed up to 25 +/- 4%. After infusion of P and A a distinct vasoconstriction could be seen. Especially P showed a decrease in diameter of almost 25% in small coronary segments (less than 2.0 mm diameter). The dilatative effect of G i.v. seems to be important in the therapy of acute ischemic situations, for instance, for unstable angina, acute myocardial infarction, or during PTCA. The acute coronary vasoconstriction after infusion of P and A should be considered when used in acute ischemic events.