Background Oxidation and inflammation caused by lower limb ischemia–reperfusion (I/R) readily induce lung injury. We elucidated whether cepharanthine, a potent antioxidative and anti-inflammatory drug, can mitigate lung injury induced by lower limb I/R. Role of heme oxygenase 1 (HO-1) was also investigated. Materials and methods Adult male Sprague–Dawley rats were randomized to receive I/R, I/R plus cepharanthine, or I/R plus cepharanthine plus the HO-1 activity inhibitor tin protoporphyrin (SnPP; n = 12 in each group). Sham control groups were run simultaneously. I/R was induced by applying rubber band tourniquets high around each thigh for 3 h followed by reperfusion for 24 h. Results Rats receiving I/R had significant increases in concentrations of nitric oxide, malondialdehyde (lipid peroxidation marker), and inflammatory molecules (including interleukin 6, macrophage inflammatory protein 2, and prostaglandin E 2 ) in plasma, and the lungs, indicating that I/R caused significant oxidation and inflammation in rats. Rats receiving I/R also had significant increases in concentration of phosphorylated inhibitor-κB, indicating that I/R caused significant nuclear factor κB activation. Assays of arterial blood gas, biochemistry, and histopathology confirmed that I/R-induced significant lung injury in rats. Cepharanthine significantly reduced the oxidation, inflammation, nuclear factor κB activation, and lung injury induced by I/R. Of note, cepharanthine significantly enhanced pulmonary HO-1 expression after I/R. Moreover, these previously mentioned effects of cepharanthine were partially reversed by inhibiting the activity of HO-1. Conclusions Cepharanthine mitigates lung injury induced by bilateral lower limb I/R in rats. The mechanisms may involve its effects on reducing oxidation and inflammation. The mechanisms may also involve enhancing HO-1 expression. [ABSTRACT FROM AUTHOR]