- Coca Cola can be used on a wasp sting (but not bee) in an emergency. The phosphoric acid can help inactivate the alkaline wasp venom. The same is true for jelly-fish stings in case you don't have any vinegar handy.
- While not strictly medical, coca cola can be used to fade hair dyes and clean stains including blood. However Mythbusters showed that it wasn't a particularly good cleaning agent, and does not dissolve rust or teeth/T-bones for that matter...
- Rehydration for infants suffering from diarrhea. While any sweet water will do, it is often the only "clean" liquid available in less fortunate parts of the world...
- Dissolving phytobezoar. These are undigested clumps of plants that can accumulate and block the stomach. Think of it as a human "hairball" (pictured above) and check out the awesomely disgusting examples here.
- As a contraceptive. However this was disproved by the winners of this year's IgNobel.
"The results indicate: (a) an increase in body weight in all treated animals; (b) a statistically significant increase of the incidence in females, both breeders and offspring, bearing malignant mammary tumors; (c) a statistically significant increase in the incidence of exocrine ademonas of the pancreas in both male and female breeders and offspring; and (d) an increased incidence, albeit not statistically significant, of pancreatic islet cell carcinomas in females, a malignant tumor which occurs very rarely in our historical controls."
However since the control was drinking water I'm not sure what you can conclude from this study other than it's probably not a good idea to substitute all drinking water to a sweet liquid.