This study investigated the analgesic effects of taraxeren-3-one, which is an ingredient from Diospyros maritima (DM), using the models of acetic acid-induced writhing response and the formalin test, and its anti-inflammatory effects using the model of λ-carrageenan (Carr)-induced paw edema. Treatment of male ICR mice with taraxeren-3-one inhibited the numbers of writhing response and formalin-induced pain in the late phase, significantly. In the anti-inflammatory test, taraxeren-3-one decreased paw edema at 4 and 5 h after Carr administration and increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) in the liver tissue at 5 h after Carr injection. Taraxeren-3-one affects malondialdehyde (MDA), nitric oxide (NO), and tumor necrosis factor-α (TNF-α) levels from both the edema paw and serum at 5 h after Carr injection. Western blotting revealed that taraxeren-3-one decreased Carr-induced inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) expressions. These anti-inflammatory mechanisms of taraxeren-3-one might be related to the decrease in the level of MDA in the edema paw via increasing the activities of SOD, CAT, GPx, and GSH in the liver. Also, taraxeren-3-one could affect the production of NO and TNF-α and, therefore, affect the anti-inflammatory effects.