AIM: To investigate the anti-inflammatory effects of the sesquiterpenes α-humulene and β-caryophyllene on pterygium fibroblasts. METHODS: Primary cultures of pterygium fibroblasts were established. Third passage pterygium fibroblasts were exposed to α-humulene and β-caryophyllene separately and together. The cell viability was assessed by 3- (4,5-dimethylthiazolyl-2) -2,5-diphenyltetrazolium bromide (MTT) assay at 12, 24, 48, and 72h after exposure. The levels of the inflammatory cytokines interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α and IL-10 in the conditioned culture medium were assessed by enzyme-linked immunosorbent assay (ELISA) at 12, 24 and 48h after exposure. Data were statistically analyzed using Friedman repeated measures analysis of variances on ranks. RESULTS: The 25 μmol/L β-caryophyllene induced significant decrease in the IL-6 production by pterygium fibroblasts 48h after the exposure (P=0.041). The levels of IL-1β, IL-8, IL-10, and TNF-α were very low and had no statistically significant variations after exposure to α-humulene, β-caryophyllene, or both compounds together. CONCLUSION: The exposure to 25 μmol/L of β-caryophyllene significantly reduce the production of IL-6 by pterygium fibroblasts after 48h. This sesquiterpene may be a potential alternative adjuvant agent for the treatment of pterygium.