The water-soluble iodine-containing contrast media diatrizoate sodium (Oral Hypaque) and diatrizoate methylglucamine (Gastrografin) have greatly extended the scope of gastrointestinal x-ray diagnosis. They are essentially unabsorbed from the intestinal tract, but are non-toxic if introduced into body cavities. The two media are used interchangeably in the hospital from which this report comes in situations where opaque material in the intestine will contribute to diagnosis, but barium is contraindicated. That these substances can contribute significantly to evaluation of occult intestinal perforation recently came to our attention (Case I). In 4 subsequent patients, opacification of the bladder after diatrizoate ingestion was found to be an exceedingly valuable sign in recognizing questionable or obscure intestinal (in 1 instance esophageal) perforation. One false positive was noted (Case VI). Case I: A 15-year-old girl was admitted with severe abdominal pain. Two hours after diatrizoate ingestion for eva...