The present study aimed to investigate the effect of RNA interference (RNAi) on the inhibition of interleukin (IL)‑6 expression in rat cerebral gliocytes in vitro and rat cerebral traumatic tissues in vivo, as well as the effect of RNAi on cerebral edema. pSUPER vectors containing IL‑6 small hairpin RNA (pSUPER‑IL‑6 1‑5) were designed, constructed and transfected into C6 rat glioma cells using cationic liposomes. ELISA was used to select the plasmid with the strongest interference effect. A freefall method was used to generate a rat brain injury model and rats were randomly divided into treatment, empty plasmid and control groups (n=14/group). IL‑6 levels, water content and sodium content were determined in the brain tissues at 24 and 72 h post‑injury. pSUPER‑IL‑6 was effectively transfected into C6 cells and was found to inhibit the expression of IL‑6 rather than IL‑8. The pSUPER‑IL‑6 1 vector was most effective in inducing RNAi. In vivo, IL‑6 levels were observed to be lowest in the interference group and there were statistically significant differences in water and sodium content among the experimental groups (P<0.05). RNAi was found to inhibit IL‑6 expression in vivo and in vitro in rat cerebral gliocytes, and the reduction of the IL‑6 levels was found to reduce post‑traumatic cerebral edema.