(1) Six 3-dialkylaminomethyl-7-chloro- and six 3-dialkylaminomethyl-7-methoxy-thromanones, structurely derived from Miracil B, were prepared for the purpose of finding an effective drug in the treatment of Schistosomiasis Japonica. (2) The aqueous solutions of 3-dialkylaminomethyl-chromanones were not stable and yielded precipitate as the result of decomposition. Prom the solutions of 7-chloro-derivatives we isolated the identical product of m.p, 104-105°, while from those of 7-mcthoxy-derivatives we obtained the other identical product of m.p. 66-67°.