In order to compare the anti-ischemic activity of gallopamil and nifedipine, a cross-over, double-blind, randomised trial was carried out in 30 male out-patients with a history of stable exertional angina, proven coronary disease and a positive stress test (ST-segment depression > or = 1 mm). After a first 1-week wash-out period on placebo, the patients were randomised to gallopamil, 150 mg/day (50, 50 and 50) or nifedipine, 30 mg/day (10, 10 and 10) for 28 days. After a second 1-week wash-out period active treatments were crossed for another 28 days. At the end of each drug or placebo period, a physical examination, laboratory tests and a stress test were performed. Oral short-acting nitrates were permitted throughout the trial periods. Twenty-one patients finished all periods of the study. Both drugs reduced the maximum ST-segment depression during the exercise test: from 2.45 +/- 0.97 mm (placebo) to 1.95 +/- 0.82 mm (gallopamil, P < 0.05) and from 2.50 +/- 0.93 mm (placebo) to 1.75 +/- 0.84 mm (nifedipine, P < 0.05). Gallopamil but not nifedipine increased stress tolerance significantly: from 486 +/- 156 s (placebo) to 598 +/- 138 s (gallopamil, P < 0.05) and from 509 +/- 113 s (placebo) to 567 +/- 191 s (nifedipine, NS). No significant differences were found between drugs. Both calcium antagonists, gallopamil and nifedipine, showed similar efficacy in treating myocardial ischemia.