The authors use methotrexate (MTX) to induce lung fibrosis in rats through a single intraperitoneal injection. While methotrexate is generally known as a chemotherapeutic and immunosuppressive agent, it is not typically associated with causing lung cancer in rats. However, chronic exposure to MTX can lead to lung toxicity, including conditions such as fibrosis and pneumonitis, rather than directly causing cancer. Therefore, if they are using methotrexate to induce lung fibrosis, it is essential to administer it over an extended period to ensure that sufficient lung fibrosis develops before proceeding with treatment using the methanolic extract of the aerial parts of Halleria lucida