Systolic time intervals were measured from simultaneous high speed recordings of the electrocardiogram, phonocardiogram, and carotid artery pulse in 15 men with chronic severe anaemia not in heart failure and with a normal heart size, and in 15 normal men. Heart rates, electromechanical systole (QS2), pre-ejection period index (PEPI), left ventricular ejection time index (LVETI), and the ratio of pre-ejection period to left ventricular ejection time (PEP/LVET) did not differ significantly in the two groups. After the intravenous administration of frusemide in 10 of the anaemic patients, the pre-ejection period index was prolonged, the PEP/LVET ratio increased, heart rate increased, and the left ventricular ejection time index shortened. Intravenous digoxin did not alter the QS2 interval and heart rate significantly in the anaemic subjects. Left ventricular function in chronic severe anaemia as measured by systolic time intervals does not differ from that of normal controls. The effect of frusemide on the systolic time intervals is explained as an effect of the fall in preload, bringing cardiac function further down on the ascending limb of the Frank-Starling curve. Other related studies are discussed.