Traditional herbal medicine is used extensively among the Korean populations, and other Asian countries employ similar therapies as well In recent years, extensive focus was laid on adulteration of the herbal medicine with heavy metals. This may be mainly due to a soil contamination by an environmental pollution. The objective of this study is to identify the contents of various heavy metals in the blood from OhJeokSan-Decoction (OD) treated-rats. For this study, 13 kinds of metals including essential and heavy metals, i.e. Al, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se and Zn were analyzed by a slight modification of EPA methods and the following results are obtained. ; 1. There is no significant difference between the OD-treated groups and control group in liver, kidney, bone, brain, weight, food intake. 2. The amount of each metal analyzed in the liver are as follows; Al ; $0.235{sim}4.215mg／kg$, As ; $0.103{sim}0.461mg／kg$, Cd ; $0.005{sim}0.010mg／kg$, Co ; $0.017{sim}0.046mg／kg$, Cr ; $0.137{sim}0.403mg／kg$, Cu ; $1.736{sim}4.827mg／kg$, Fe ; $54.472{sim}381.447mg／kg$, Hg ; not detected, Mn ; $1.159{sim}2.803mg／kg$, Ni ; $0.007{sim}0.095mg／kg$, Pb ; not detected, Se ; $0.682{sim}1.887mg／kg$, Zn ; $10.213{sim}26.119mg／kg$, by groups, respectively. In control and other experimental group, several metal (Co, Cu, Mn, Zn, As, Cr) has a significant difference, but in experimental I and other experimental II, III, IV, V groups, there are no significant difference. 3. The amount of each metal analyzed in the kidney are as follows; Al ; $1.712{sim}31.230mg／kg$, As ; $0.062{sim}0.439mg／kg$, Cd ; $0.010{sim}0.062mg／kg$, Co ; $0.000{sim}0.101mg／kg$, Cr ; $0.125{sim}0.636mg／kg$, Cu ; $3.385{sim}12.502mg／kg$, Fe ; $41.148{sim}99.709mg／kg$, Hg ; $0.000{sim}0.270mg／kg$, Mn ; $0.433{sim}2.301mg／kg$, Ni ; $0.000{sim}0.221mg／kg$, Pb ; $0.000{sim}0.584mg／kg$, Se ; $0.540{sim}1.600mg／kg$, Zn ; $8.775{sim}17.060mg／kg$, by groups, respectively. The concentration of Cu, Se, Cr, and Hg are variated significantly in control and other experimental group, and Cu, Se, Cd, Cr are variated significantly in experimental I and other experimental II, III, IV, V groups. 4. The amount of each metal analyzed in the bone(tibia and fibula) are as follows; Al ; $9.557{sim}119.464mg／kg$, As ; $0.139{sim}12.250mg／kg$, Cd ; $0.000{sim}0.295mg／kg$, Co ; $0.022{sim}0.243mg／kg$, Cr ; $0.239{sim}1.999mg／kg$, Cu ; $0.000{sim}2.291mg／kg$, Fe ; $240.249{sim}841.956mg／kg$, Hg ; $0.000{sim}0.983mg／kg$, Mn ; $0.214{sim}7.353mg／kg$, Ni ; $5.473{sim}11.453mg／kg$, Pb ; $0.000{sim}8.502mg／kg$, Se ; $0.000{sim}3.005mg／kg$, Zn ; $61.158{sim}195.038mg／kg$, by groups, respectively. The concentration of Se, Cd are variated significantly in control and other experimental groups, and Se is variated significantly in experimental I and other experimental II, III, IV, V groups. 5. Exceptionally several metal concentration is increased or decreased. but there is no significant harmful difference of metal concentration in the liver, kidney and bone, from the OD-treated-rats compared to those of the control group even if higher dosage($1{sim}8$ times dosage of person) of OD was administered. Thus, it is expected that the herbal decoction in the traditional herbal medicine would not lay any burden on the body and the heavy metal toxins would not affect our physiological system. However, other kinds of herbal treatment, such as i.v. and i.p. should be considered in terms of metal toxicity in the body since ..