Recent studies emphasize the presence of alveolar tissue inflammation in asthma. Immunotherapy has been considered a possible therapeutic strategy for asthma and its effect on lung tissue had not been previously investigated. Measurements of lung tissue resistance and elastance were obtained before and after both ovalbumin and acetylcholine challenges. Using morphometry, we assessed eosinophil and smooth muscle cells density as well as collagen and elastic fibers content in lung tissue from guinea pigs with chronic pulmonary allergic inflammation. Animals received seven inhalations of ovalbumin (1~5mg/mL-OVA group) or saline (SAL group) during four weeks. Oral tolerance (OT) was induced by offering ad libitum ovalbumin 2% in sterile drinking water starting with the 1st inhalation (OT1 group) or after the 4th (OT2 group). The ovalbumin-exposed animals presented an increase in baseline and in post-challenge resistance and elastance related to baseline, eosinophils density, and collagen and elastic fibers content in lung tissue compared to controls. Baseline and post-ovalbumin and acethylcholine elastance and resistance, eosinophil density, and collagen and elastic fibers content were attenuated in OT1 and OT2 groups compared to OVA group. Our results show that inducing oral tolerance attenuates lung tissue mechanics as well as eosinophilic inflammation and extracellular matrix remodeling induced by chronic inflammation.