After dimercaptosuccinic acid (DMSA) was given intragastrically by gavage (ig) 0, 250, or 500 mg.kg-1 following in CuSO4 30 mg.kg-1 daily x 3 d in rats, the Cu contents of serum increased markedly within 1-12 h. When ig DMSA daily x 3 d, the excretion of Cu in urine per 24 h in the treated group was greatly promoted vs the control (P < 0.01), that in the 250 or 500 mg.kg-1 group were enhanced 2.4-3.8 and 5.8-7.8 times, respectively. That the excretion of Cu was increased in bile but not in feces suggested the plausible existence an enterohepatic circulation.