New submitter redhat_redneck writes "The U.S. and Canada has been experiencing a shortage of barium sulfate, which is used as contrast for upper and lower GI studies. It has reached the point where doctors are being asked not to order these exams except in emergencies, and some exams are being cancelled. Here's the letter that's been put out by the manufacturer. The longer this drags on, the more serious this issue becomes, eventually impacting patients and healthcare providers in both cost and quality of care. Some sources point to a dramatic drop in Chinese production. In their defense, it seems China is changing safety regulations. Medical use only make a fraction of the uses of barium sulfate, but it's going to be disproportionately affected by this shortage. We can't go back to our old contrast Thorotrast; it causes cancer. Does anyone know of alternatives to barium?"