Pathophysiological mechanisms for vasospasm after subarachnoid haemorrhage (SAH) remain unclear and, so far, roles of cytokines in vasospasm have not been known. In the present study, we measured interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumour necrosis factor-alpha (TNF-alpha) concentrations in the cerebrospinal fluid (CSF) of patients with subarachnoid haemorrhage (SAH). ELISA assay were performed on 21 CSF samples from 7 patients with SAH and on 4 sera samples. Both IL-6 and IL-8 were detected in all CSF samples, but IL-1 alpha, IL-1 beta, and TNF-alpha were not detected. IL-6 and IL-8 were also detected in sera, but at much lower concentrations. This study indicates that IL-6 and IL-8 may play roles as immunomodulators in patients with SAH. In addition, it has been reported that IL-6 inhibits prostaglandin I2 production and increases the mRNA level of c-sis gene, suggesting that IL-6 may play an important role in vasospasm as vasoconstrictor.