Examination of the aerial parts of Boronia algida has led to the isolation of six coumarins, an alkaloid and a triterpene. The coumarins were identified as (+)-marmesin, 7-demethylsuberosin, 5-deoxyprotobruceol-II hydroperoxide, a mixture of the diastereomers of 5-deoxyprotobruceol-III 3'xi-hydroperoxide and 3'-hydroxyxanthyletin; the alkaloid as 1-methyl-2-pentadecyl-4(1H)-quinolone and the dammarane triterpene as (E)-25-hydroperoxy-3 beta-hydroxydammar-20,23-diene. The latter compound and 3'-hydroxyxanthyletin are novel natural products. The chemotaxonomic significance of these isolates in the genus Boronia is discussed.