ETHNOPHARMACOLOGICAL RELEVANCE: Thai herbal Kratom (THK), a traditional Thai remedy for muscle pain, is composed of six important medicinal plants and has been traditionally used as a compressed ball for muscle pain management. This study aimed to evaluate its phytochemical composition and biological properties, including antioxidant, anti-inflammatory, and analgesic actions. MATERIALS AND METHODS: The phytochemical profile was investigated, and antioxidant activity was assessed using DPPH and ABTS scavenging assays. In vivo anti-inflammatory properties were examined using carrageenan-induced rat paw edema and ethyl phenylpropiolate (EPP)-induced ear edema, while anti-nociceptive activity was explored by the hot plate test and acetic acid-induced writhing test. RESULTS: The ethanolic extract of THK was found to contain several potent phytochemicals, including 4-hydroxycoumarin, curcumin, mitragynine, aloin A, and limonin. HPLC analysis revealed a high concentration of mitragynine in the extract, with a value of 10.76 ± 0.50 mg/L. The extract demonstrated an antioxidant activity in DPPH and ABTS scavenging assays, with IC CONCLUSION: This study found that the ethanolic extract of THK possesses significant anti-inflammatory and analgesic activities in vivo, supporting its traditional use for muscle pain management.