E-Z-EM, Inc, Westbury, NY, offers Tagitol, a tagging agent developed to improve visualization of the bowel during virtual colonoscopy examinations. Tagitol, a radiopaque contrast medium, works by marking any stool remaining in the colon to distinguish it from surrounding tissue. A low-density suspension of barium sulfate, the lemon-lime-flavored product comes in 250 ml dose bottles for administration with meals prior to the procedure. (516) 333-8230; www.ezem.com.