The aim of the study is to investigate chemical constituents of the leaves of Pieris japonica. The isolation and purification of the constituents were performed by various chromatography and spectral analysis. Three new phenolic glucosides, erythro-syringoylglycerol 4-O-beta-D-glucoside (1),
A new phenolic glycoside, benzyl 2-hydroxy-4-O-β-D-glucopyranosyl-benzoate (1), along with nine known flavonoids, epicatechin-(2 → O → 7,4 → 8)-ent-epicatechin (2), bis-8,8'-catechinylmethane (3), quercetin (4), quercetin-3-O-α-L-arabinfuranoside (5), quercetin-3-O-α-L-rhamnopyranoside (6), astilbin