Bryonia laciniosa Linn. (Family: Cucurbitaceae), is an annual climbing herb. Traditionally, it is mentioned in the Ayurvedic text in Vrishya Rasayana category and highly valued as a female fertility booster. The present study involves the isolation and identification of isoquercetin from methanolic extract of Bryonia laciniosa by using TLC, UV, FTIR, 1HNMR and HR-LCMS techniques. The structure of the isolated compound was established by High-Resolution Liquid Chromatogram Mass Spectrometry and proton-NMR. The mass spectra of compound produced molecular ion peak (m/z) at 469.07. Proton- NMR showed two proton signals of H-6 and H-8 of ring ?A? and three aromatic proton signals of H-6?, H-2? and H-5? of ring ?B? confirming 3?,4? dihydroxy structure in the isolated compound corresponding to the aromatic ring ?B? of quercetin nucleus. The signal of glucose moiety at δ 5.299 indicated the isolated compound has β- linked glucose. Thus, confirming the isolated compound as isoquercetin, a flavonoid glucoside. This is the first paper to report a flavonoid from Bryonia laciniosa.