. The bark is thick, deeply furrowed and dark colored.Large pockets of kino were observed formed by the breaking down of tissues of the outer phloem. Themean chemical composition of E. sideroxylon bark was: ash 1.3%; total extractives 55.7%, mainly corre-sponding to polar compounds that were soluble in ethanol and water, lignin 13.1% and suberin 1.9%.The polysaccharides composition showed predominance of glucose and xylose (80.0% and 11.0% of totalneutral monosaccharides respectively). The ethanol–water bark extract had a high content of pheno-lics: total phenolics 440.7 mg gallic acid equivalent/g extract, flavonoids 204.4 mg catechin equivalent/gextract and tannins 395.0 mg catechin equivalent/g extract. The antioxidant activity corresponded to648.8 mg Trolox/g of extract, and FRAP values to 5247 mM Fe2+/g of extract. E. sideroxylon bark can there-fore be extracted with green solvents to yield polar extractives with a potential valorization based ontheir chemical functionalities and bioactivity.