This study was performed to investigate the preventive effect of KDD against lead toxicity. KDD of 133, 266, 532 and 1,064 mg/kg were administered twice to the rats of Sprague-Dawley strain and then 300 mg/kg lead acetate was given to times, respectively. 1. The $delta$-ALAD concentration in the urine showed 10.6 ~16.4 mg/kg in the control group indicated statistical significance for the experimental group II, III, IV, V (p<0.05). Also, the Coproporphyrin concentration had 0.119 ~ 0.226 $mu$g/ml in the control group indicated statiscial significance for the experimental group V of 10 weeks (p<0.05). 2. The $delta$-ALAD concentration in the blood showed 13.28 ~ 16.08 ALAD unit in the control group indicated statistical significance for the experimental group I (Pb 300 mg/kg) of 6 and 8 weeks, for the experimental group III, IV of 8 and 10 weeks, and for the experimental group V of 4 weeks (p<0.05). The $delta$-ALAD concentration of experimental group I (Pb 300 mg/kg) group was inclined to decrease during the experiment period. The $delta$-ALAD concentration of experimental group I (Pb 300 mg/kg) showed statistical significance for the experimental group II, III, IV, V of 6, 8 and 10 weeks. But, there was no statistical significance in the concentration change of hemoglobin, RBC, WBC, hematocrit, Ca, protein among the experimental groups. In conclusion, this study revealed the preventive effect of KDD against lead toxicity and its mechnism inferred to facilitate lead excretion in urinary following hinderance of lead absorption in the gastric-intestine and organs.