This paper presents a case of 16-year-old schoolboy who injected subcutaneously about 6 ml of metallic mercury to both forearms and administered orally about 5 ml of it. The patient was admitted to hospital two weeks after this incident without any clinical symptoms. Physical examination and all laboratory tests, including chest x-ray were unremarkable except for granulomata at the injection sites. X-ray examination showed numerous, dispersed globules of mercury in subcutaneous tissue of both forearms and in the digestive tract, mainly in the appendix. Granulomatous tissue with a part of mercury from both forearms as well as appendix were surgically removed. During a six-month period no toxic effects of mercury have been observed, in spite of the fact, that blood mercury level was 132 micrograms/L and urinary mercury level was 500 micrograms/L.