The Centers for Disease Control and Prevention has redefined the threshold of concern for low-level lead toxicity, reducing it from a blood lead level of 25 micrograms per dL (1.21 mumol per L) to a blood lead level of 10 micrograms per dL (0.48 mumol per L), and has recommended universal screening of young children. Succimer (2,3-dimercaptosuccinic acid) is an effective oral lead chelating agent that has been approved for outpatient treatment of children with blood lead levels higher than 45 micrograms per dL (2.17 mumol per L). In the United States, clinical experience with succimer is limited; however, observed side effects, including gastrointestinal symptoms, rash and transient elevations of serum aminotransferase levels, are uncommon and mild. Isolated cases of neutropenia have been reported. Weekly monitoring of complete blood counts and serum aminotransferase levels is recommended during the 19-day treatment. Blood lead levels should be checked weekly to identify rebound from bone and soft tissue mobilization.