Two new acridone alkaloids, named furoparadine (1) and trans-dihydroxycitracridone-I (2), were isolated from the root of Marsh grapefruit (Rutaceae) and their structures were elucidated on the basis of spectroscopic methods.In our continuing research on the constituents of Citrus plants, we have reported the isolation and structure elucidation of many acridone alkaloids and coumarins. As a part of this program, we recently reported the isolation of new acridone alkaloids, named citbismine-A, marshdine, and marshmine from the roots of Marsh grapefruit (Citrus paradisi Macf.). Further investigation of this plant furnished to isolate two new acridone alkaloids, furoparadine (1) and trans-dihydroxycitracridone-I (2). This paper deals with details of structure elucidation of these new alkaloids.