OBJECTIVES: We wanted to investigate the efficacy of dimercaptosuccinic acid (DMSA) for the treatment of lead poisoning in an adult. METHODS: The chelation therapy was applied using oral DMSA after measuring the blood lead and performing, renal function tests, liver tests and a physical examination. This therapy with oral DMSA 30 mg/kg/day was administered three times a day for 5 days to an adult patient with a pre-chelation blood lead concentration of 75 microgram/dL. Testing was performed by assessing the daily blood lead level, the blood ZPP, the urine ALA, the symptoms and side effects were assessed by conducting a physical examination. RESULTS: DMSA therapy given for the duration of 5 days reduced the blood lead concentration from 75 microgram/dL to 21.8 microgram/dL. The blood ZPP concentration fell from 366 microgram/dL to 300 microgram/dL. The urine ALA concentration fell from 9.71 mg/L to 0.38 mg/L. In addition, the symptoms of headache, dizziness and abdominal pain that were induced by lead were improved after 2 days of chelation therapy. The vomiting did not improve after 5 days of chelation therapy, but this resolved 14 days following cessation of therapy. No adverse effects of DMSA therapy were seen. CONCLUSIONS: Oral chelation therapy with DMSA 30 mg/kg/day is possible without being admitted to a hospital and it is generally effective, safe, and relatively inexpensive. DMSA provides a positive effect on adult patients who have lead poisoning.