This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on Barium. "Ingestion of certain forms of barium (e.g., barium carbonate or barium fluoride) in toxic amounts leads to gastrointestinal symptoms (e.g., vomiting, abdominal pain, and watery diarrhea). Within 1--4 hours of ingestion, profound hypokalemia develops in certain instances, and potassium levels <1.0 mmol/L are associated with generalized muscle weakness that might progress to paralysis of the limbs and respiratory muscles (1-5). Barium sulfate is not absorbed when taken by mouth and is therefore commonly used as a contrast agent for radiographic procedures."
Centers for Disease Control and Prevention: http://www.cdc.gov/