PURPOSE--To analyze adverse reactions (AR), hemodynamic and electrocardiographic changes and thallium scintigraphy (TS) results, during pharmacological stress with dipyridamole (SD), correlating these data to the presence and extension of coronary artery disease (CAD). METHODS--We studied 126 patients, 66 had no evidence of cardiovascular disease (G1) and 60 had critical occlusive CAD > or = 70 per cent stenosis (G2). Most of them were male, mean age 56.5 +/- 10.9 years old. All patients were submitted to TS after receiving 0.56 mg/kg of dipyridamole intravenously (0.14 mg/min during 4 min) followed by 111MBq of thallium-chloride-201. Conventional ECG was recorded before and after SD; heart rate (HR) and arterial pressure (AP) were monitored during dipyridamole infusion. All signals and/or symptoms were observed. RESULTS--Cine-coronarography showed 22 patients (37 per cent ) with one vessel disease (VD) (G2a), 26 (46 per cent ) with two VD (G2b) and 12 (20 per cent ) with three VD (G2c). Of the 126 patients 63 per cent did not present symptoms. Flushing (25 per cent ) and sick-headache (12 per cent ) were most frequent AR. Typical angina was reported by one G1 patient (1.5 per cent ) and six G2 patients (10 per cent ) (p < 0.05). HR increased 18.09 +/- 12.27 per cent and 12.40 +/- 4.90 per cent , systolic blood pressure varied -5.2 +/- 7.5 per cent and -4.3 +/- 6.5 per cent in G1 and G2, respectively. These parameters are not correlated to CAD presence and extension. ST depression and ectopic beats occurred in 5 per cent and 11 per cent of G1 patients, in 15 per cent and 30 per cent of G2 patients, respectively (p < 0.05). Typical angina was more common in G2a and G2b; ST changes in G2b and G2c; and arrhythmia in G2c (not significant). Sensitivity of TS associated to SD was 84 per cent , comparable to stress exercise thallium test. CONCLUSION--TS associated to SD, a noninvasive, safe with low morbidity and few collateral effects method is an option to patients with limitations to physical exercise tests