The effect of changes in body weight, some blood components and some inorganic ions in liver and kidney, were studied on male rats receiving ad libitum on 5, 40, and 200 ppm of mercuric chloride solution during so days. The results obtained were summarized as follows ; 1. The total body weights were decreased in proportion to increment of mercury concentration. The internal organs weights i. e. , liver, kidney, spleen, and heart, were generally increased. Especially, the weight increment of kidney was the highest by intaking of mercuric chloride solution. 2. There were no significant changes in hematocrit values, activities of GOT and GPT in blood of rats receiving mercuric chloride. On the other hand, the plasma levels of cholesterol were significantly increased. The receiving of 200 ppm mercuric chloride solution to rats was resulted in the remarkable reduction of total protein levels and A/G ratio in plasma. 3. The markable rise occured in the accumulation of Hg, in both liver and kidney in proportion to supplying in rats while there was a tendency decreasing of Cu, Zn contents in liver, whereas there was a tendency increasing of Cu, Zn in kidney of rats.