Cola was used in traditional medicine in Africa to settle the stomach.!
I once lived in a part of the world where food hygene was pretty poor. Having ended up in what passed as a local hospital with food poisoning (treated by the biggest injection I have ever seen right in my rear end) [...supplied my own syringe and needle] I discovered the coke cure.
The cure was brutal but seemed to work. At the very first symptoms of food poisoning I would drink a litre of water and make myself puke it up. I would then drink a litre of flat coke, wait an hour and puke it up. I would then drink another litre of water, puke it up and another litre of water and puke that up. While this was horrible it was very much better than the food poisoning. I am not recommending that anyone else tries this BTW.
The theory is that the acid in the coke kills the food poisioning bacteria. Sort of sounds unlikely but as I said it did appear to work.