Head trauma and severe cerebral hemorrhage are major risk factors for development of ventilator-associated pneumonia. In a previous open labelled, single center study the investigators showed that repeated oropharyngeal decontamination with povidone-iodine may be an effective strategy to decrease the prevalence of ventilator-associated pneumonia in patients with head trauma. The present study aims to confirm these results in a multicenter, double blind study including patients suffering from head trauma or cerebral hemorrhage.