eugenia malaccensis l. (syzygium malaccensis merr. & perry), popularly known in brazil as jambo vermelho, is a very common tree and one of the medicinal plants of alagoas state, brazil. previous chemical studies with e. malaccensis have been carried out with native plants from asia, oceania, and central america. this work describes the chemical study of e. malaccensis l., a specimen collected in alagoas state. considering that studies on the molluscicidal and larvicidal potential of e. malaccensis were not reported, this work aimed to test its molluscicidal activity against biomphalaria glabrata snails and larvicidal activity against aedes aegypti mosquitos. the ethanolic stem bark and leaf extracts were inactive towards aedes aegypti larvae. the ethanolic stem bark and leaf extract were active against biomphalaria glabrata with cl50 = 42.53 and 41.90 mg/ml, respectively. 5,7,3',4',5'-penta-hydroxy-flavonol (1), 5,7,3',5'-tetra-hydroxy-4'-methoxy-flavonol (2), 3,4,5-tri-hydroxybenzoic acid (3) and 3-acetyl-urs-12-en-28-oic acid (4) were isolated and identified from the leaves and stem bark. the acid 3b-o-acetyl-urs-12-en-28-oic is for the first time isolated from the genus eugenia. the structures of the compounds have been established by ir, 1h and 13c nmr spectral analysis and by comparison with literature data.