[en] Non-toxic bromofluorocarbon radiopaque agents are disclosed. Certain monobrominated acyclic fluorocarbons, e.g., CF3(CF2)6CF2Br, are improved non-toxic radiopaque agents useful in diagnostic roentgenology, for example in visualizing the gastrointestinal tract, the tracheobronchial tree, the alveolar spaces or parenchyma of the lung, the spleen, the urinary bladder and ureters, the common bile duct and its radicals, the pancreatic ducts, the blood vessels, etc. 13 claims, no drawings