A phytochemical investigation of the ethyl acetate fraction of root bark extract of Synadenium glaucescens Pax (Euphorbiaceae) led to the isolation of two derivatives of ellagic acid. These included one new 3′,4′ -di-O-methylellagic acid-4α, L-rhamnopyranoside (1) and a known 3,4,3′-tri-O-methylellagic acid (2). Their structures were elucidated by 1D and 2D NMR, while a High res. MS (FTMS-ESI^–) was used for accurate mass measurement, which was compared with SciFinder data as well as with available literature. The BSLT results indicated that both 1 (LC₅₀ = 2736.03 μg/mL) and 2 (LC₅₀ = 531.19 μg/mL) were nontoxic at a maximum test concentration of 2400 ppm.