Recently, pentraxin 3 (PTX3), a protein induced by proinflammatory signals produced by neutrophils, macrophages, myeloid dendritic and endothelial cells, has emerged as a key player in local inflammatory and ischaemic events, and it has been proposed as a valuable prognostic and diagnostic tool in many conditions, substantiating the evidence that PTX3 has useful features for a potential biomarker. In this context, Zanier [49] investigated the concentrations of PTX3 and its relation with SCV in the plasma and cerebrospinal fluid (CSF) of 38 aSAH patients. PTX3 was elevated in all SAH patients in both plasma and CSF. Early, acute peak CSF PTX3 was significantly higher in patients who later developed vasospasm [median 13.6 (range 2.3-51.9) ng/ml] compared to those who did not [3.2 (0.1-50.5) ng/ml, p = 0.03]. The temporal pattern of CSF PTX3 in patients with vasospasm was triphasic, with a peak during the first 48 h after SAH, a subsequent decrease in the following 48-96 h, and a secondary significant increase with the occurrence of vasospasm. The measurement of CSF PTX3 can improve early diagnosis of this complication, and will be evaluated as a potential early biomarker in further researches. Even if we are improving in the identification of potential biomarkers to use as an early warning for CVS, this search is not yet concluded, and in the future we will probably ameliorate our comprehension in this exciting field.