The aim of this study was to investigate the effects of yerba mate (Ilex paraguariensis St. Hil.) extract (YME) on oxidative stress parameters and pathological changes in the lungs of mice chronically exposed to hand-rolled cornhusk cigarette (HRC) smoke. Twenty-four male Swiss mice were divided into four groups exposed to the following treatments: control (ambient air), HRC, YME, and HRC plus YME. The animals were exposed to four HRCs per session, with 3 sessions/day, every day for 30 days. Twenty-four hours after the last inhalation, the mice were killed, and the left lungs were removed. The results showed that HRC contains elevated levels of tin and carbon oxide, but less arsenic, cobalt, manganese, and selenium than commercial cigarettes. YME administration reversed fibrosis, alveolar enlargement, and hemorrhage induced by HRC smoke. In addition, the YME and HRC significantly reduced the production of oxidants, oxidative damage and promoted a significant increase in total thiol. In conclusion, exposure to HRC smoke compromised pulmonary histoarchitecture by promoting structural changes and increasing oxidative stress in tissues. However, concomitant treatment with YME regulated the redox state and reduced the harmful effects of HRC smoke exposure in the lungs.