The seaweeds are important sources for generating new products with biotechnological potential. The secondary metabolites found in macroalgae are obtained by extraction processes using organic solvents. However, there is scant data in the literature about the morphology of the macroalgae before and after the extraction process. The aim of this work was to verify the morphology and chemical composition of macroalgae – Dictyota menstrualis (brown algae), before and after the extraction process with organic solvents using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Based on micrographic analysis, it was possible to verify the morphological differences of the biomass samples. Before the extraction process, Dictyota menstrualis showed dense morphology, and after the extraction process, it presented lamellar morphology, whose chemical composition consisted of the elements carbon, oxygen, sodium, magnesium, aluminum, silicon, sulfur, chlorine, calcium, potassium, and iron.