Objective To observe the effects of dexmedetomidine on cerebral extraction ratio for oxygen (CERO2) and cerebrospinal fluid (CSF) amino acids in patients who underwent a glioma resection.Methods A total of 60 patients who underwent a glioma resection were enrolled and divided into test group and control group using the single-blind random method, with 30 cases in each group. After general anesthesia, the test group was given dexmedetomidine, and the control group was given an equivalent amount of normal saline. The two groups were compared for hemodynamic indices (heart rate and mean arterial pressure) and CERO2 before anesthesia (T0), during tracheal intubation (T1), during craniotomy (T2), and at the end of operation (T3) as well as levels of CSF amino acids (inhibitory amino acid γ-aminobutyric acid[GABA] and excitatory amino acids aspartic acid[Asp] and glutamic acid[Glu]) before operation and at 6 h and 24 h after operation.Results The heart rate and mean arterial pressure in the test group at T1 and T2 were significantly lower than those at T0, and they were also significantly lower than those in the control group (P<0.05). The CERO2 levels in the test group at T1, T2, and T3 were significantly higher than those at T0, and they were also significantly higher than those in the control group (P<0.05). The test group had a significantly higher level of GABA and significantly lower levels of Asp and Glu in the CSF than the control group at 6 h and 24 h after operation (P<0.05).Conclusions Dexmedetomidine can increase CERO2, maintain hemodynamic balance and stability, and improve CSF amino acid expression in patients who underwent a glioma resection, thus protecting the brain.