Objective To preliminarily investigate the effect and possible mechanisms of Senecio cannabifolius Less.Ⅱ(FHC-Ⅱ) on perfluoroisobutylene (PFIB) inhalation-induced acute lung injury. Methods Totally 156 rats were randomly assigned to three groups: the control group, the PFIB group and the FHC-Ⅱ prevention group, with 32, 62 and 62 rats in each group respectively. The FHC-Ⅱprevention group were given FHC-Ⅱthree times per day at the dosage of 340 mg/kg before PFIB exposure. 1 h after the last time of FHC-Ⅱ administration, the FHC-Ⅱ prevention group were exposured to gaseous PFIB (0.2 mg/L) for 10 minutes in a static whole-body exposure inhalation system. The survival rate of the rats were recorded at 1, 2, 4, 8, 16, 24, 48 and 72 h post PFIB exposure;the lung index and total protein content in bronchoalveolar lavage fluid (BALF) were measured at 1 h, 2 h, 4 h, 8 h, 16 h and 24 h; IL-1β and IL-8 in sera were assayed by enzyme-linked immunosorbent assay (ELISA) at 1, 2, 4, 8 and 16 h post PFIB exposure and the histopathological examination of the lung tissue was performed at 8 h post PFIB exposure. Results FHC-II significantly reduced the content of the total protein in BALF, lung index and the levels of IL-1β and IL-8 in aera as well, and dramatically alleviated the histopathological changes in the lung tissue. Conclusion FHC-Ⅱ demonstrates some preventive effect on PFIB inhalation-induced acute lung injury in rats.