Four new dihydrostilbenes, alpha,alpha'-dihydro-3,5-dihydroxy-4'-acetoxy-5'-isopentenylstilbene (1), alpha,alpha'-dihydro-3,3',4'-trihydroxy-5-O-isopentenyl-6-isopentenylstilbene (2), alpha,alpha'-dihydro-3,5,3'-trihydroxy-4'-methoxystilbene (3), and