The aim of this study was to investigate the ability of sodium metabisulfite (SMB) which is used as an antimicrobial substance in food, to induce chromosome aberrations (CA) and sister chromatid exchanges (SCE) in human lymphocytes. SMB-induced CAs and SCEs at all concentrations (75, 150 and 300 mug/ml) and treatment periods (24 and 48 h) dose-dependently. However, SMB decreased the replication index (RI) and the mitotic index (MI) at the concentrations of 150 and 300 mug/ml for 24 and 48 h treatment periods. This decrease was dose-dependent as well. (C) 2001 Elsevier Science B.V. All rights reserved.