Abstract： Objective To explore the effect and safety of hyperbaric oxygen(HBO)therapy on acute cerebral infarction in early period.Methods Ninty patients with first-time acute anterior cerebral infarction were randomly assigned into two groups and 45 patients were in each group.HBO group were treated with HBO within 12 hours,while control group were not treated with HBO.Results At 14,28 and 90 days after treament,NOS(neuro-deficit score)and score of ADL(activities of daily living)in HBO group were higher than those in control group(P＜0.05).There were no serious adverse effects in the two groups.Conclusions HBO treatment can improve NOS and ADL of patients with acute cerebral infarction in 12 hours at 0.22 MPa.At the sanle time,HBO therapy is safe to acute cerebral infarction.