In this communication, chemical transformations of luguine (II), a new alkaloid isolated from Glaucium flavum Cr. var. vestitum, are described and these, together with physical evidence, have led us to establish structure (II) for the new alkaloid, which is the first example of a 6-hydroxy benzophenanthridine alkaloid where ring C is aromatic. Luguine (II) was isolated as yellow crystals, mp 282-284°C (from ethylacetate), [α]₂₀^D +172° (c=0.05, dioxan) which analyzed for C₁₉H₁₃O₅N. Mass spectrometry confirmed the molecular ion as 335 and indicated the presence of a hydroxy group. Its structure was elucidated by spectral (UV, IR, pmr, off-resonance C-13 nmr) and chemical evidence: O-acetylation to a monoacetate (establishing a secondary hydroxyl group) and dehydration to norsanguinarine (IV) (confirming the benzophenanthridine skeleton). The absolute configuration (6S)-(+) was unambiguously determined by chemical correlation with (-)-norchelidonine (I) via dehydrogenation (using I₂/NaOAc in abs.EtOH or DDQ in dioxan), as (-)-norchelidonine has an S configuration at C-6. This work identifies luguine (II) as the first 6-hydroxy benzophenanthridine alkaloid with an aromatic ring C.