BACKGROUND: The aetiology of the reduced systemic vascular resistance and abnormal 'filling' of the vascular bed in cirrhosis is still obscure. As increased concentrations of the potent vasodilator calcitonin gene-related peptide (CGRP) have recently been reported in cirrhosis, we related CGRP to central and peripheral haemodynamics in patients with cirrhosis. METHODS: Thirty-one cirrhotic patients and six control subjects underwent an investigation with determination of systemic haemodynamics and circulating CGRP. RESULTS: Circulating CGRP was significantly increased in patients with cirrhosis (P < 0.02) and covaried directly with the severity of cirrhosis (P < 0.02). The increased CGRP covaried negatively with the reduced systemic vascular resistance (P < 0.02), the reduced central blood volume (P < 0.01), and reduced central circulation time (P < 0.002) and positively with the non-central blood volume (P < 0.05). CONCLUSIONS: These results suggest that increased CGRP may play a role in the systemic vasodilatation in cirrhosis and may contribute to the abnormal distribution of the blood volume, which may lead to abnormal sodium and water handling.