The purpose of the study was to determine the toxicity of inhaled cadmium (Cd) on hepatic biochemical function. Male rats and rabbits were exposed for 2 hr to concentrations of 0.25, 0.45, and 4.5 mg Cd/cu m. Xenobiotic metabolizing enzymes, serum and liver enzymes, and histological changes were studied. Exposure to 4.5 mg/cu m CdCl2 and CdO resulted in an increase of liver Cd content in both rat and rabbit. Following exposure to 4.5 mg/cu m CdCl2, decreases in body and liver weight, and decreased activities of glutathione (GSH)-reductase, GSH-peroxidase, and glucose-6-phosphate dehydrogenase (G-6-PDH) were observed in rat liver. Exposure to a similar concentration of CdO caused decreased liver activities of GSH-reductase and peroxidase, G-6-PDH. The 0.45 mg/cu m exposure to CdCl2, collectively produced more hepatic effects in both rat and rabbit than did a similar exposure to CdO. The differential response was probably due to a more rapid clearance of CdCl2 or Cd+2 ions from the lung and transport to the liver via the systemic blood circulation as compared to CdO.