Many fruits of the Myrtaceae have a rich history of use both as edibles and as traditional medicines in divergent ethnobotanical practices throughout the tropical and subtropical world. From South America to Southeast Asia, these fruits have been used for a wide variety of ailments, including cough, diabetes, dysentery, inflammation and ringworm. These same fruits are also used to make many food products. Based on information regarding ethnomedical use, known phytochemistry, fruit color, popularity as edibles and availability, the fruits of several edible species from the subtribe Eugeniinae have been selected for phytochemical analysis in an attempt to discover new antioxidants. The fruits of six species in this group have shown a strong antioxidant activity in the 1, 1-diphenyl-2-picrylhydrazyl chemical assay. The UV absorbance spectrum of the most active compound in Eugenia uniflora L. indicates that it is a flavonoid. Polyphenolic compounds like flavonoids have an enormous range of biological activity and are known to inhibit oxidative damage in vivo better than the classical vitamin antioxidants. In plants, they protect against lipid peroxidation and UV damage that can affect tropical fruits growing under severe conditions including high heat and intense sunlight.