<jats:p> A preliminary examination of Dicentra canadensis tubers collected in the province of Quebec has revealed the presence of protopine, which had previously been found, together with three typical alkaloids of Corydalis species, namely: bulbocapnine, corydine and isocorydine. The presence of the last in comparatively large quantity is surprising in view of its general scarcity elsewhere. The existence of other bases is indicated and will be made the subject of studies on a larger quantity of material.Of the non-basic materials, the most interesting is a nitrogenous orange-colored substance, C<jats:sub>32</jats:sub>H<jats:sub>29</jats:sub>O<jats:sub>5</jats:sub>(OMe)<jats:sub>3</jats:sub>(− CON =)<jats:sub>2</jats:sub>, the complexity of which is reminiscent of oxyacanthine or dauricine.