Eight patients had unusual reactions, including hypotension and bradycardia, to i.v. contrast media [Conray-60, Hypaque-25, Conray, Conray-400, Cholegrafin, Renografin-30, Renografin-60). These reactions appear to be vagal- or acetylcholine-mediated. Atropine treatment produced prompt reversal in several of the cases, and is felt to be the drug of choice for this particular type of idiosyncratic reaction.