To study the effect of small amounts of ethanol 1 ml whisky (43 vol. %) per kg body weight was given to normal subjects (n = 11) and patients with coronary heart disease (n = 11) and the systolic time intervals (STI) PEP (preejection period), LVET (left ventricular ejection time), QS2 (total electromechanical systole) and PEP/LVET were measured. A control group consisted of five patients with coronary heart disease. The following results were obtained: Already at rest PEP/LVET was significantly higher in patients with coronary heart disease. After the ingestion of alcohol, significant changes of the STI were observed; mainly an increase of PEP and PEP-LVET was found. In patients with coronary heart disease the effect began earlier, was significantly higher and lasted significantly longer than in normal subjects. According to invasive correlation-studies of different authors, these results indicate an impairment of left ventricular function, especially of ejection fraction and contractility. These alterations seem to be more pronounced in patients with coronary heart disease. The results of this study should be considered in advising patients with coronary heart disease.