Objective: To study the effect of capsaicin gel (local product) on temporomandibular joint (TMJ) pain. Methods: A randomized, double blind, placebo-controlled study was performed on 9 Thai patients suffering from acute TMJ pain. The patients were divided into experimental (5 subjects) and placebo (4 subjects) groups; and evaluated to indicate the musticatory muscles and TMJ pain. The maximum mouth opening was measured and recorded in mm. The 100 mm visual analog scale (VAS) was also used to identify the TMJ pain level before application the gels. The patients were instructed to apply 0.02 ml of 0.025% capsaicin gel or its vehicle to painful area, 4 times daily for 4 weeks. Pain relief was, then, assessed each week on VAS. Muscle and joint sensitivity to palpation on the painful joint and maximal mouth opening were examined weekly by the same experienced examiner. Results: The application of capsaicin gel showed TMJ pain relief. The mean VAS scores of experimental group were decreased significantly during the experimental peroid (mean ± SD before: 46.20 ± 16.02; after 4 weeks: 17.60 ± 17.11, p<0.05). In contrast, the application of placebo gel had no benefit on TMJ pain. The mean VAS scores of placebo group were not statistically difference (before: 22.25 ± 15.62; after 4 week: 16.25 ± 13.75, p>0.05). Conclusion: The application of Thai capsaicin gel reduced acute TMJ pain.