Background: The traditional medical treatment of acute heart failure (AHF) has remained unchanged for many years. It has been based on oxygen supplementation and mechanical ventilatory support as well as the administration of morphine, diuretics, nitrates and inotropic agents. In 2005 the European Society of Cardiology (ESC) published new guidelines on the diagnosis and treatment of AHF. Also, new therapies have been introduced recently, giving rise to changes in therapeutic concepts. Material/Method: Based on these new guidelines and recent studies selected from the literature we here describe the new ESC classification of AHF including its epidemiology and pathophysiology. We further present a state-of-the-art status of the choices of medical treatment for patients with acute decompensated heart failure and pulmonary edema. Results: Mechanical ventilatory support reduces the number of patients who require endotracheal intubation.Nitrates in dosages higher than employed today appear to be beneficiary to patients with pulmonary congestion, probably because of the pronounced afterload-reducing effect. Nesiritide, a synthetic brain natriuretic peptide, has shown better hemodynamic effects than common nitrate dosages in patients with congestive heart failure. Tezosentan, an endothelin antagonist, was tested in the biggest AHF trial ever, which, however, was terminated prematurely because it was futile to proceed given the endpoints dyspnea and death. The β1-adrenergic drug dobutamine and the phosphodiestherase inhibitor milrinone are associated with increased mortality in patients with pronounced chronic and acute congestive heart failure. Levosimendan, a new inotropic drug, has shown lower mortality compared to dobutamine in patients with acute congestive heart failure. Conclusion: New concepts have finally emerged, including the application of old drugs such as nitrates in new (i.e., higher) dosages, as well as the novel compound levosimendan, recommended for patients with AHF and hypoperfused organs. The new ESC classification of AHF provides a valuable and long-awaited guideline to diagnose and treat this severe condition.