Aspidosperma macrocarpon Mart. (Apocynaceae) is used in popular medicine to treat malaria and dengue. The aim of the present study was to morphoanatomically, histochemistry and phytochemically characterize A. macrocarpon young branches and leaves, seeking to indicate secondary compounds presenting medicinal potential to treat these diseases. Aspidosperma macrocarpon young branches and leaves were collected in private properties located in municipality of Alta Floresta, Mato Grosso State, Brazil. Sectional and paradermic sections were set freehand using a steelblade, were doubly stained and assembled on histological slides. The fresh material was subjected to histochemical and phytochemical tests for detection of saponins, tannins, alkaloids, flavonoids, cardiotonic glycosides, anthraquinone, steroids and terpenes. Aspidosperma macrocarpon presented glandular trichomes, cavities and secretory cells. We detected the presence of tannins, flavonoid, phenolic compounds, cardiotonic glycosides and alkaloids, which may confer antiplasmodic activity and antiviral properties to the species. As far as it is known, the present study was the first to identify aspects of the histochemical and phytochemical composition of young branches and leaves A. macrocarpon which may be associated with the popular use of this plant to treat malaria and dengue in a transition region between the Cerrado and Amazon biomes, where malaria and dengue occur endemically.