In myocardial infarction (MI), the sooner thrombolysis is performed, the greater the chances of it being effective. We report a 19-month experience (July 1, 1986 to December 31, 1987) of thrombolysis performed at home prior to hospitalization by an organization called SOS Myocardial Infarction (SOS MI). Method. Throughout 24 hours, any patient may call by telephone a doctor attached to SAMU 13. If the doctor suspects a coronary emergency, he sends to the patient's home the SOS MI team (1 doctor and 1 nurse) in a medically-equipped ambulance. The diagnosis of MI is made on the finding of a nitroglycerin-resistant chest pain of more than 30 minutes duration associated with a more than 2 mm elevation of the ST segment on at least two electrocardiographic leads. Patients aged under 70 and in whom thrombolytic drugs are not contra-indicated are then treated intravenously with either streptokinase (1.5 million units over 30 min) or the tissue plasmogen activator (10 mg followed by a 90 mg infusion over 90 min). Results. During the 19-month period, 648 coronary emergencies were suspected from data given by telephone. The diagnosis made by the SOS MI doctor was non-coronary chest pain in 119 cases (18.4 p. 100), angina pectoris in 211 cases (32.6 p. 100).(ABSTRACT TRUNCATED AT 250 WORDS)