Although there have been several reports of adverse reactions to contrast material during barium gastrointestinal (GI) studies, these are considered highly unusual. During a 27-month period at the author's institution, seven reactions to contrast material occurred during 6,918 colon examinations, and four reactions to contrast material occurred during 11,534 upper GI procedures. This frequency is greater than what has been reported previously. Most reactions were fairly mild, with urticaria and pruritus, although two patients, both with a history of asthma, had severe reactions that required emergency treatment. One patient had similar adverse reactions during both upper and lower GI examinations. Since only two patients received glucagon, this is not believed to be a factor. It is likely that patients react to some additive in the barium suspension. The radiologist must be aware of these complications and be ready to begin appropriate treatment.