February 3, 2010 - Most toothpastes use saccharin as a sweetener. The U.S. Food, Drug and Cosmetic Act's Delaney Clause prohibits the use of "any food additive that has been shown to cause cancer when ingested by humans or animals."
"The Cancer Testing Technology and Saccharin" report, published in 1977 by the Board of the Office of Technology Assessment, reviewed saccharin tests and reported no link between bladder cancer in human males and use of artificial sweeteners. A Canadian study reported after the U.S. study did find a link between the two. Both studies were done on a limited number of participants (only 632 in the Canadian study), and both were limited to studying only a correlation to bladder cancer.
If you have concerns about artificial sweeteners, choose saccharin-free toothpaste by Trader Joe's, Kiss My Face or Burt's Bees. (Tom's of Maine now has questionable ingredients since being purchased by Colgate.)