Chamomile (Chamomilla recutita), is one of most commonly used species in herbal medicine and is included in the pharmacopoeia of almost all countries. Some of the known pharmacological effects are attributed to the presence of secondary metabolites, but it is not known whether other molecules such as polysaccharides, are working together to these effects. There are few studies on the chemical structure and biological activity of chamomile polysaccharides. Therefore, the present study aimed to structurally characterize and evaluate the antinociceptive effect of a glucuronoxylan polysaccharide isolated from infusion (tea) of chamomile. After a series of ultrafiltrations, Fehling and enzymatic treatments, an homogeneous fraction was obtained and analyzed by sugar composition, HPSEC and NMR spectroscopy analysis. The results showed that the fraction is composed of a 4-O-methyl-glucuronoxylan, consisting of a main chain of →4)-β-D-Xylp-(1→ units alternating with →2,4)-β-D-Xylp-(1→, with 4-O-Me-α-D-GlcpA-(1→ as non-reducing end units. Intraperitoneal administration of this polysaccharide at 10 and 30 mg/kg showed a decrease of mice nociception in acute and inflammatory phases on formalin model. Due to symptoms such as drowsiness and piloerection, open field test was performed to verify if the polysaccharide could be affecting the locomotor system of animals. From this test, it was observed a decrease in locomotion of the animals and this result indicates that the sample may have produced a false positive result on mice nociception and the real activity can be sedating or both effects.