The phytochemical study of flowers and green fruits of Senna spectabilis furnished a new substituted 2,6-dialkylpiperidin-3-ol alkaloid, named (-)-7-hydroxycassine, along with five known piperidine alkaloids: (-)-cassine, (-)-spectaline, (-)-3-O-acetylspectaline, (-)-7-hydroxyspectaline and (-)-iso-6-spectaline. In addition to non-alkaloidal, chemical constituents from other chemical classes were also identified, including the steroid β-sitosterol, the flavonoids luteolin and 3-methoxyluteolin, the triterpene betulinic acid and trans-cinnamic acid. To our knowledge, compounds are being reported for the first time in this species. © 2013 Sociedade Brasileira de Quimica.