<p>Thermogravimetry coupled to Fourier-transform infrared spectroscopy (TGA/FTIR) was used to analyze the evolved gases from pyrolysis of four different lignocellulosic fibers (abaca, hemp, henequen, and coconut) that contain variable percentages of cellulose, hemicellulose and lignin. TGA results revealed that although the fibers exhibited different thermal stabilities (henequen had the highest decomposition temperature while coconut reported the lowest), the thermal decomposition pattern was similar as all samples displayed two degradation stages. By comparing representative spectra of the evolved gases at each stage for all-natural fibers, it was observed that during the first emission, the released gases were different and varied depending on fiber type. In contrast, during the second emission, similar spectra were obtained for all-natural fibers. Thus, it was found that during the first stage, abaca fibers release mainly carbon dioxide, hemp fibers evolve gases containing hydroxyl and carbonyl functionalities, whereas henequen and coconut ones produce carbon dioxide and gases that contain compounds possessing carbonyl and hydroxyl functional groups. During the second stage, all samples released carbon dioxide as well as compounds containing carbonyl, hydroxyl, and aliphatic functional groups.</p> Graphical abstract <p></p>