Objective To observe the clinical efficacy of Chaigui granules in the treatment of type III prostatitis with water stasis syndrome and its impact on prostate fluid cytokines and other indicators. Methods Patients diagnosed with water stasis type III prostatitis were randomly assigned to either a treatment group consisting of 35 cases or a control group comprising 27 cases.The control group was given sustained-release capsules of tamsulosin hydrochloride orally, while the treatment group was given Chaigui granules orally. Compare the chronic prostatitis symptom Index (NIH-CPSI) score, changes in prostate fluid cytokines, and clinical efficacy between two groups of patients before and after treatment. Results The national institutes of health chronic prostatitis symptom index (NIH-CPSI) scores in the treatment group showed a significant reduction after the treatment when compared to their scores before treatment (P<0.05). This decrease was also notably greater than the scores in the control group after treatment. Additionally, the levels of interleukins IL-2, IL-6, and IL-8 in the treatment group showed a significant reduction post-treatment compared to their levels before treatment (P<0.05). The levels of IL-2 and IL-6 were significantly lower in the treatment group than in the control group post-treatment. Furthermore, when comparing the total effectiveness rates of traditional Chinese medicine syndromes between the two groups, the treatment group demonstrated a significantly higher effectiveness rate than the control group(P<0.05). Conclusion Chaigui granules can significantly improve the clinical symptoms of patients with type III prostatitis with water stasis syndrome, and enhance clinical efficacy. Its mechanism may be related to the regulation of cytokine levels in prostate fluid, which is worth further research.