Reflex sympathetic dystrophy is a major complication following surgical treatment of fractures of the distal radius. Its pathogenesis is related to lipid peroxidation which damages vascular endothelial cells, increasing capillary permeability. Vitamin C is a natural antioxidant. The authors have made a comparative study of two groups of patients with isolated closed displaced fractures of the distal radius, which were reduced and stabilized by intrafocal pinning. Group 1 included 100 patients who were treated from 1995 until 1998 and who did not receive any vitamin C supplementation; group 2 included 95 patients who were treated from 1999 to 2002 and who received daily administration of one gram vitamin C orally during 45 days, starting on the day of fracture. The incidence of reflex sympathetic dystrophy was five time times lower in group 2 (2.1% versus 10%). This is in line with previous observations and lends credit to the value of vitamin C administration as a prophylactic measure to prevent the occurrence of reflex sympathetic dystrophy in patients who undergo surgical treatment of a displaced fracture of the distal radius.