What's worse when you're scheduled for a colonoscopy – the procedure itself or the quarts of nasty liquid you drink beforehand? For patients who are facing one variant of the procedure, the doctors at Mayo Clinic may have good news.

Under a new practice at Mayo Clinic in Arizona, four pills replace the multiple liters of laxative for people having a CT colonography also known as a virtual colonoscopy. In virtual colonoscopies, a CT scan is used to provide three-dimensional imaging of the colon and rectum. They and regular colonoscopies, in which a tiny camera is inserted into the body, both require a laxative to empty the colon.

In the new Mayo protocol that began this summer, patients having virtual colonoscopies simply take four tablets of the cleansing agent bisacodyl.

"Our hope is that this will make people less anxious and more likely to get screened and will ultimately result in fewer deaths from colorectal cancer," says C. Daniel Johnson, M.D., chair of the Department of Radiology at Mayo Clinic in Arizona.