1. Central and peripheral haemodynamic effects of intravenous infusion of angiotensin II have been investigated in ten normotensive subjects. Angiotensin II was given at the rate of 0·12–5·0 μg/min.
2. The pressor response to angiotensin II was accompanied by a significant increase in the total peripheral resistance, central venous pressure and by a marked reduction of the intravascular forearm volume and venous distensibility. Forearm circulation time was shortened.
3. Cardiac index, heart rate, forearm vascular resistance and the forearm blood flow did not change significantly in the whole group but in the individual subjects some of the variables changed markedly in either direction.
4. Direct action of angiotensin II on the vessels and its central and peripheral sympathomimetic action as well as the role of the baroreflex as responsible causes for haemodynamic changes after angiotensin II are discussed.