Induced blood pressure elevation has become a popular treatment for intracranial hypertension. However, there remains a concern that in some patients blood pressure elevation will further elevate ICP. This study was conducted to test the hypothesis that increasing MAP decreases ICP. A total of 47 studies were performed on 23 intubated patients with head injury. MAP and SjvO2 were continuously monitored. MAP was raised significantly by 13.8 (5.9) mmHg (t-test; p < 0.0001) using phenylephrine infusion. The percent change ICP per mmHg increase in MAP (% delta ICP/mm Hg MAP) was calculated. Pearson correlation coefficient, t-test and logistic regression analysis were used for statistical evaluation. Increasing MAP resulted in a decrease in ICP in 38.3% and in an increase in ICP in 61.7% out of 47 studies. The following characteristics were seen in patients in whom a decrease in ICP was associated with an increase in MAP: High GCS (r = -0.61; p = 0.004) and low SjvO2 ((2 = 4.89; p = 0.027). In patients with lower GCS and high SjvO2 an increase in MAP resulted in an increase in ICP. We concluded that in the majority of studies increasing MAP was followed by an increase in ICP. CPP therapy has a selective indication in patients with high GCS, low SjvO2 and increased ICP.