The excretion of cadmium through the bile and gastrointestinal mucosa after the intraperitoneal administration of cadmium chloride and the effect of the chelating agents such as ethylenediaminetetraacetic acid, citric acid, 2, 3-dimercapto-1-propanol, L-cysteine, D-cysteine, and DL-penicillamine on its excretion were studied in rats. The cumulative biliary excretion of cadmium in a 9 hr period was about 0.85% of the injected dose. Citric acid, D-cysteine, and DL-penicillamine increased the biliary excretion of cadmium. All of the chelating agents used scarcely affected the excretion of cadmium through the gastrointestinal mucosa. Moreover, chemical characteristics of cadmium complex in the bile were investigated by the chromatography on Sephadex G-75 of the bile from the rats receiving cadmium chloride. The results showed that cadmium was bound to several bile components with different molecular weights, and that cadmium in the bile of the rats administered cadmium chloride with the chelating agents such as citric acid, D-cysteine, and DL-penicillamine was largely bound to the substances with a low molecular weight.