The present study was conducted to analyse the effect on haemodynamics and to evaluate the role of hypoxic pulmonary vasoconstriction (HPV) in cirrhotic patients with hypoxaemia using almitrine bismesylate, an agent which increases the response of HPV. Six male patients, mean age of 51 years, with hepatic cirrhosis and associated hypoxaemia were studied. All patients had normal lung and cardiac function tests. When the patients were clinically stable, right heart and radial artery catheterization were performed. Data from the pulmonary artery catheter and blood gases were obtained before and after 4 days of oral almitrine bismesylate. The results indicated that these cirrhotics were in a mild hyperdynamic circulatory state. The cardiac output (CO), cardiac index (CI), oxygen delivery (DO2), and oxygen consumption (VO2) were elevated while the pulmonary vascular resistance (PVR) and systemic vascular resistance (SVR) were low. Almitrine significantly increased PVR (P < 0.05) and mean pulmonary artery pressure (mPAP) (P < 0.01). In addition, almitrine improved alveolar arterial oxygen content difference [D(A-a)O2] (P < 0.01) and shunt fraction (Qva/QT) (P < 0.01). The PaCO2 and PaO2 increased slightly but this was not statistically significant. In conclusion, in our group of patients with hepatic cirrhosis, four days of treatment with almitrine improved their gas exchange. The data suggest a weak HPV response in this group of cirrhotics; that response may be enhanced by almitrine.