A single-blind study was performed on male workers from a primary lead smelter to determine whether a daily oral supplement of vitamin C (1 g vitamin C orally once a day, five times a week for 20 weeks) or zinc (60 mg zinc as zinc gluconate once a day, five times a week for eight weeks) influences the absorption of and the biological (hematological and renal) response to lead. The vitamin C and the zinc study groups comprised 39 and 11 workers, respectively. Their blood levels of lead at the start of the experiment ranged from 28.9 to 76.4 μg/100 ml. A matched control group receiving a placebo was followed simultaneously. The results demonstrate that, in workers whose exposure to inorganic lead is moderate and who do not suffer from nutritional deficiencies, oral supplementaion of vitamin C or zinc does not influence the metabolism and biological action of lead.