Two new triterpenoids, maquatic acid (1), a 2,3-seco-triterpene having an acetal in its A-ring, and 3-Ο-benzoyltormentic acid (2), were isolated from underground parts of Mentha aquatica, in addition to twelve known compounds, tormentic acid (3), 1-Ο-benzoylhyptadienic acid (4), 3-epi-ursolic acid