Abstract Background: Studies have shown that the overall incidence rate of herpeszoster (HZ) in China is 6.64 cases per 1000 people, despite such harms brought by postherpetic neuralgia (PHN), the mechanism of the disease remains unclear in China. Currently, effective biomarkers to predict PHN remain unavailable, which makes it difficult to prevent and successfully treat PHN. Objectives: The aim of the study was to determine the serum interleukin-6 level in PHN. Methods: The serum levels of interleukin 6 (IL-6) were measured by multi-antibody sandwich ELISA. The likert scale was used to represent the degree of neuralgia in the patients. Patients with PHN were divided into a mild PHN group and a severe PHN group according to the Likert scale. ROC curve was performed for evaluating the diagnostic efficiency of IL6 for PHN. The correlation between the IL6 level and the Likert scale before and after treatment with gabapentin and mecobalamin was analyzed. Results: IL6 levels in PHN patients resulted higher compared to volunteers. Patients in the severe PHN group had a higher serum IL6 level than in the mild PHN group. The Likert scale score was related to the serum IL6 levels and the frequency of IL6 levels above the cutoff value (4.95pg/mL) in PNH groups before and after treatment (p<0.05). Study limitations: Pain is subjective. Some mental states, such as anxiety and depression, greatly influence an individual’s perception of pain, and pain tolerance can vary between people. Therefore, pain scores can be affected by different individual factors. Conclusions: The serum IL6 levels may be used as a biochemical indicator of the severity of PNH.