1. The effect of intravenous ergotamine on general (blood pressure and cardiac output) and regional (splanchnic, renal and muscular) haemodynamics was studied immediately and 3 h after administration in seven male volunteers. Also plasma catecholamines were determined.
2. An increase in blood pressure with a peak just after administration was observed. The cardiac output was unchanged and the pressor effect of ergotamine was due to an increase in total peripheral resistance.
3. Plasma noradrenaline decreased 65% at the peak of the pressor effect whereas plasma adrenaline was unchanged.
4. Hepatic blood flow decreased 34% just after ergotamine administration and was normal after 3 h. Renal blood flow decreased by 29 and 19%. Calf blood flow was unchanged. These results suggest that different vascular beds in man react differently to ergotamine.