<jats:title>Abstract</jats:title><jats:p>A methanol extract of the bark of <jats:italic>Bocconia arborea</jats:italic> was fractionated on silica gel and the fractions analysed using gas chromatography coupled with mass spectrometry (GC‐MS). Several benzophenanthridine alka‐loids were identified including dihydrosanguinarine, oxysanguinarine, 11‐acetonyldihydrochelerythrine, dihydrochelerythrine, chelerythrine, chelerythridimerine and angoline as the principal constituents. The results show that the direct GC‐MS analysis of these alkaloids is possible with a clear distinction between the compounds. The technique is shown to be a valuable tool and an alternative technique to classical phytochemical procedures permitting the fast analysis of alkaloids mixtures. Copyright © 2002 John Wiley & Sons, Ltd.