Based on my discussions with my doctor relatives, a healthy mucosal lining in the stomach protects it from the acidic damage that Coke (not to mention your stomach acid) can do. Now, it's my personal hunch that the high phosphorus content of any carbonated soft drink forces the body to leach calcium into the bloodstream to regulate the calcium-phosphorus ratio, but I've been shouted down by Coke lovers already in another thread.