Sixty-six subjects selected at random during the routine work of a medical outpatient department, without typical cardiac complaints, aged 58.4 +/- 8.2 years, and 29 patients in the third week after a new myocardial infarction aged 55.8 +/- 6.9 years drank on fasting a suspension of 450 mg dipyridamole. The ECG tracing was made on fasting, 45 and 60 minutes after ingestion of the suspension, on development of angina pectoris immediately and then aminophylline was administered by the i.v. route. In the first group there were 4.5%, in the second group 24.1% positive tests of coronary insufficiency. The oral test replaces the intravenous dipyridamole test. It is suitable as a supplementary test for the assessment of coronary insufficiency in combination with ergometry and as an alternative examination where ergometry cannot be performed.