In the taxonomy of angiosperm plants, floral characters have generally been preferred over vegetative characters, as evidenced in many of the classification, systems; however, these can vary significantly, making it difficult in some cases to identify plant species. Chemotaxonomy or chemosystematics, evaluates the presence of chemical compounds in plant species; the chemical aspect of the classification of plants is based on their constituents, that is, on their molecular characteristics; These, like morphological characteristics, are genetically controlled, but have the advantage over morphological ones, of being able to be described exactly in terms of defined structures and configurational chemical formulas. In this study, it was proposed to determine the presence of phenolic compounds (Flavonoids) in the foliar ethanolic extracts of the Ficus benjamina L; Ficus insipid Willd; Ficus elastica Roxb ex Hornem and Ficus bullenei I.M. Johnst species, in order to apply the comparative method of chemical structures and the existing taxonomic relationship between the investigated species, from the chemotaxonomic point of view. On the other hand, the antioxidant activity of the foliar ethanolic extracts of the species F. benjamina, F. insipida, F. elastica and F. bullenei was evaluated, using the methods DPPH• (2,2- Diphenyl-1picrilhidrazil), ABTS+• (Acid 2,2'-azino-bis (3-ethylbenzothiazoline-6 sulphonic)) and FRAP (Iron Reduction Antioxidant Potential). For this, a range of working concentrations between 1 and 6 mg / L was established for all extracts. The IC50 values determined by the DPPH• method were 5.4 mg/L, 4.8 mg/L, 2.4 mg/L and 3.9 mg/L, respectively. For the ABTS+• method, the IC50 values calculated were 2.9 mg/L, 2.8mg/L, 3.7mg/L and 3.0 mg/L, for each species respectively. For these two methods 6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid (Tolox) was used as a reference. The FRAP method was used with a concentration range between 1 and 5 mg/L. All the foliar ethanolic extracts evaluated presented iron reduction potential, the most active being the extract of the Ficus elastica species and the one with the lowest potential against the TPTZ complex, was the foliar EtOH extract of the F. bullenei species, compared to the substance of reference (Gallic acid).