To evaluate the safety of intravenous dipyridamole thallium-201 imaging as an alternative to exercise thallium imaging in the evaluation of coronary artery disease, clinical data from 140 patients were retrospectively analyzed. Adverse effects were experienced by 39 patients (27.9%) with a total number of 52 effects: chest pain (23), dizziness (13), headache (7), nausea (7), dyspnea (2). All patients presented complete relief of symptoms. In 15 patients administration of aminophylline was necessary. Major effects (fatal and non fatal myocardial infarction and acute bronchospasm) were not registered. Vital sign data change observed after infusion of dipyridamole was: decreased blood pressure and increased pulse rate. Patient's age and incidence of coronary artery disease did not differ significantly in the subgroup of patients with adverse effects versus the group of patients without it.