1-Hydroxy-2,3,4,7-tetramethoxyxanthone, with an EC50 value of 6.6±1.4 µM, has vasodilatory action in coronary arteries pre-contracted with 1 µM 5-hydroxytryptamine (5-HT) and can effectively inhibit osteoclast differentiation in a co-culture system with mouse osteoblastic calvarial cells and bone marrow cells.