Background: In recent years, studies have shown that electronic WOM (eWOM) directly reflects consumers’ post-purchase psychological perception and directly affects repurchase behavior. This information is valued by institutions in various fields. Within the scope of the evaluation of service characteristics, medical service is the least visible and most difficult service attribute to evaluate. Service organizations must have high trust attributes. Therefore, an eWOM review significantly influences people’s decision-making process when choosing a healthcare provider. The purpose of this research is to combine eWOM reviews with the SERVQUAL scale in a comparative study of positive and negative eWOM reviews of a regional teaching hospital in Taiwan. Methods: This research obtained data from publicly available eWOM reviews on Google Maps of a regional teaching hospital in Taiwan over the past 10 years (from June 24, 2011, to December 31, 2021) using website scraping technology. The semantic content analysis method was used in this study to classify eWOM reviews according to the revised PZB SERVQUAL scale. Results: Statistical analysis was conducted. During the COVID-19 pandemic, positive reviews showed a downward trend. Among the five determinants of the SERVQUAL of PZB, positive eWOM reviews performed best in “assurance” with a positive review rate of 60.00%, followed by 42.11% for “reliability”. For negative eWOM reviews, “assurance” performed the worst with a positive rate of 72.34%, followed by “responsiveness” at 28.37% and “reliability” at 26.95%. Conclusion: Since the onset of COVID-19 in 2020, negative eWOM has increased significantly and exceeded the amount of positive eWOM. Regardless of positive and negative reviews, what patients care most about is “assurance” of the professional attitude and skills of medical staff, which urgently needs to be strengthened. In addition, good “reliability” will help to develop positive eWOM. However, “responsiveness” as indicated by poor service waiting time can easily lead to the spread of negative eWOM. Hospital management should focus on these service-oriented qualities.