OBJECT: This study was performed in order to examine the correlation between acute neuroleptic-induced dystonic reactions and serum iron level. METHOD: Serum iron levels were measured in psychiatric inpatients who had developed acute neuroleptic-induced dystonia(N=41) and in control patients with no history of acute dystonic reactions(N=37). Serum iron levels were compared in acute dystonic inpatients before starting treatment with neuroleptics and after acute dystonic reaction. RESULTS: The patients exhibiting acute dystonic reactions had significantly lower serum iron levels than the patients without acute dystonic reactions. CONCLUSION: This result supports an association between low serum iron and the occurrence of neuroleptic-induced acute dystonic reactions.