Analgesic effects of Goreisan in patients with glossodynia: A preliminary exploratory study

Glossodynia-related pain refers to persistent, chronic pain occurring on the oral mucosal surface. Various medications are prescribed depending on symptom profiles and have demonstrated therapeutic benefits; however, these agents are often associated with adverse effects such as drowsiness or dizziness. Goreisan, a traditional Japanese Kampo medicine, has long been used empirically for glossodynia-related pain, particularly in patients reporting symptom fluctuation associated with weather changes. Nevertheless, high-quality clinical evidence supporting its efficacy remains limited. This multicenter, randomized, open-label preliminary exploratory study enrolled patients receiving treatment for glossodynia-related pain. Participants were assigned to receive either Goreisan (7.5 g/day for 12 weeks) in addition to standard therapy or standard therapy alone. Pain intensity was assessed using the visual analog scale (VAS) at baseline and at 4, 8, and 12 weeks. Salivary amylase activity was measured as an exploratory stress-related biomarker, and atmospheric pressure was recorded at each outpatient visit. Owing to insufficient enrollment, all analyses were descriptive and exploratory. Pain intensity improved from baseline in both groups. However, the proportion of patients achieving ≥ 20% improvement in VAS at week 12 was not higher in the Goreisan group than in the control group. Weak negative correlations between VAS scores and barometric pressure were observed in both groups (r ≈ - 0.2). No clinically relevant adverse events or hepatic dysfunction related to Goreisan were identified. This preliminary exploratory study did not confirm a clear analgesic efficacy of Goreisan for glossodynia. However, the findings provide descriptive data on pain trajectories, safety, and potential meteorological associations, supporting the need for future large-scale, double-blind, placebo-controlled trials.