Ten patients with congestive heart failure (CHF), in III and IV NYHA Class, were treated orally with a single dose of ibopamine ranging from 1.2-3.3 mg/kg, and were studied using the Swan-Ganz catheter and thermodilution technique. Cardiac index (CI) and stroke volume index (SVI) were increased, and mean pulmonary pressure (PAP), systemic vascular resistances (SVR) were lowered. Ibopamine increased CI (+33%) and SVI (+26%), and decreased PAP (-17%) and SVR (-24%). All changes were statistically significant. The maximum haemodynamic effect occurred 180 min after ibopamine administration. Blood pressure and heart rate were unaffected. Tolerability was good. This study shows that ibopamine when orally administered to human subjects improves cardiac performance and further investigations on its use as a therapeutic agent in the long term treatment of CHF are recommended.