Abstract: The sympathetic nerves act on changes in cerebral blood flow. These changes have been related to changes in brain waves. Therefore, we investigated the hypothesis that changes in brain waves could be affected by changes in cerebral blood flow following a block of the Cranial Cervical Ganglion (CCG) in dogs. A total of 25 healthy beagle dogs were divided into 3 groups. Group 1 (no. = 10) underwent a block of the right CCG (rCCGB) using 1% lidocaine. Group 2 (no. = 10) served as a control for group 1. This group was injected with 1% lidocaine into the right or left side digastric muscle. Group 3 (no. = 5) served as a control for groups 1 and 2. This group underwent rCCGB using saline. After injecting drugs into the digastric muscles or CCGB, the quantitative EEG (95% spectral edge frequency (95% SEF), the Median Frequency (MF) and the relative band power (•, •, •, •), •:• ratio) was measured at 5, 10, 15, 20, 25 and 30 min for each 1 min. There was a 95% SEF increase in group 1 at 20 min and the MF was significantly decreased at 5 min and significantly increased at 15 min compared to those of the other groups (p<0.05). In the relative band power, the low frequencies (•, •) were significantly increased while the high frequencies (•, •) were decreased at 5 min (p<0.05). Thereafter, the low frequencies (•, •) were significantly decreased and the high frequency (•, •) was significantly increased between 10 and 20 min (p<0.05). The •:• ratio showed that the value decreased in the right frontal lobe. The results suggest that the rCCGB is expected to be useful in the treatment of neural and cerebral disorders in dogs because the block has a significant effect on the change of the Cerebral Blood Flow Rate (CBFr).