Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing barrows and was evaluated for its potential to ameliorate the clinical signs of aflatoxicosis. The experimental design consisted of 6 treatments of 5 barrows each at concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control), 5 g of HSCA/kg of feed (0.5%), 20 g of HSCAS/kg of feed (2.0%), 3 mg of AF/kg of feed, 5 g of HSCAS (0.5%) plus 3 mg of AF/kg of feed, or 20 g of HSCAS (2.0%) plus 3 mg of AF/kg of feed. Barrows were maintained in indoor concrete-floored pens, with feed and water available ad libitum for 28 days (from the age of 7 to 11 weeks). Barrows were observed twice daily and were weighed weekly, and blood samples were obtained weekly for hematologic and serum biochemical measurements. At the termination of the study, barrows were euthanatized and necropsied. Body weight gains were diminished significantly (P less than 0.05) by consumption of 3 mg of AF/kg of feed, whereas body weight gain in barrows consuming diets containing HSCAS or HSCAS plus AF did not differ from that in control barrows. Serum enzymatic activities of alkaline phosphatase and gamma-glutamyl transferase and prothrombin time were increased in barrows consuming 3 mg of AF/kg of feed, but not in those consuming HSCAS or HSCAS plus AF. Aflatoxin alone induced decreased serum concentrations of urea nitrogen, albumin, total protein, calcium, phosphorus, cholesterol, and glucose, as well as serum total iron-binding capacity, whereas HSCAS or HSCAS plus AF did not induce such effects. Liver weight was increased in barrows of the AF-alone treatment group, compared with control barrows. Hepatic lesions in barrows of the AF-alone treatment group were charaterized as peripheral lobular lipidosis accompanied by periportal and interlobular fibrosis and bile duct hyperplasia. Hepatic lesions were not observed in barrows of the 0.5% HSCAS plus AF or 2.0% HSCAS plus AF treatment groups. These findings suggested that HSCAS can modulate the toxicity of AF in growing barrows (perhaps via sequestration and reduced bioavailability in vivo) and may offer a novel approach to the preventive management of aflatoxicosis in animals.