Objective: This study was perfomled to examine the therapeutic effect of aqua-acupuncture solution of Hominis Placenta(HP) on kidney and liver intoxicated by $HgCI_2$ in rats. Methods: $10\%$ and $25\%$ HP aqua-acupuncture were carried out everyday for 8 days on corresponding bilateral loci of Shinsu(BL23) and Kansu(BL18), respectively, after mercuric chloride intoxication in rats. Thereafter BUN, creatinine, GOT, GPT, ALP, ${gamma}$-GT, albumin and total bilirubin were measured before intoxication, and at the 4th and the 8th experimental day. Histopathological and immunochemical observation were also carried out. Results: 1. It showed significant decreases of BUN in the group of $10\%$ HP aqua-acupuncture into Shinsu on the 4th experimental day as compared with the control group. 2. It showed significant decreases of creatinine in the group of $10\%$ HP aqua-acupuncture into Shinsu on the 4th and the 8th experimental days as compared with the control group. 3. There were not any significant changes of GOT, GPT, ALP,${gamma}$-GT, albumin and total bilirubin in the HP aqua-acupuncture groups compared with the control group. 4. By the histopathological observations on kidney under a light microscope, alt the $10\%$ and $25\%$ HP aqua-acupuncture into Shinsu showed the preventive effect on tubulo-interstitial necrosis and muItifocal calcification in tubular lumen respectively compared with the control group. 5. By the histopathological observations on liver under a light mIcroscope, the groups $10\%$ and $25\%$ HP aqua--acupuncture into Kansu did not show any significant changes in the liver compared with the control group. 6. By the immunochemical analysis of heat shock protein(hsp) and glucose-regulated protein(grp) in rat renal cortex, the expressions of hsp70 and grp78 were decreased in the $10\%$ and $25\%$ HP aqua-acupuncture into Shinsu respectively compared with the control group. Conclusion: These results suggest that Hominis Placenta aqua-acupuncture have an effect on prevention and protection of renal intoxication by $HgCI_2$ in rats.