Four alkaloids, dyshomerythrine (2), 3‐epischelhammericine (6), 2,7‐dihydrohomoerysotrine (7); and 3‐epi‐12‐hydroxyschelhammericine (8); two 1‐phenylethylisoquinoline, homolaudanosine (9) and dysoxyline (10); a novel alkaloid, dysazecine (3); two diterpenes, 8β‐hydroxysandaracopimar‐15‐ene (1) and phyllocladene (5) and p‐hydroxyacetophenone (4) isolated from the leaves of Dysoxylum lenticellare have been tested against Biomphalaria glabrata and found to possess molluscicidal activity. p‐hydroxyacetophenone (4) demonstrated high molluscicidal activity. An increase in the methoxy groupings increased the activity of the alkaloids whilst the disruption of the carbon skeleton decreased activity. All the compounds tested possessed cardiodepressant activities on the heart of B. glabrata. Copyright © 1988 John Wiley & Sons, Ltd.