Iloprost, as a stable analog of endogenous prostacyclin, has far-reaching pharmacological effects. For several years already it has been used successfully in its intravenous and inhalative forms for treating patients with pulmonary hypertension (PH). Since the development of efficient nebulizers that guarantee a constant output of the effective agent, inhalative iloprost has become an important alternative in the drug treatment of PH. Inhalative iloprost is an effective and safe partner for other classes of substances in combination therapy, which is becoming ever more frequently necessary. In addition, it is also used in the acute testing of pulmonary vasoreactivity and in intensive care therapy of manifest right heart failure.