AIM:To investigate the effect of mecobalamin via different medication method on acquired ophthalmoplegia.METHODS:Twenty-four cases(24 eyes),clinically diagnosed as ophthalmoplegia,aged from 42 to 70 years,average 58,with 13 female and 8 male were analyzed.Patients were randomly divided into group A(ion transmission),B(peribulbar injection),C(muscular injection of 0.5mg mecobalamin),D(muscular injection of 10mg vitamin B1 and 500μg vitamin B12),with 6 eyes in each group.Extravenous ocular muscle function,diplopia and oblique angles were daily monitored.RESULTS:In terms of extravenous ocular muscle function,diplopia and oblique angles,significant differences existed as comparing group A or B with group C or D respectively.Neither significant differences showed between group A and B nor between group C and D.CONCLUSION:Ion transmission of mecobalamin was confirmed as an effective,safe and convenient medication scheme.As for non-traumatic paralysis of extravenous ocular muscle,peribulbar injection can also be an option.The mecobalamin effect by local medication was found better than that by systemic one.