Dr Pepper is actually a combination of 23 different flavours. Its origin is allegedly a mixture of multiple fountain sodas. This was back in 1885 so the fountain soda pops that were mixed are not the same that you may get in a restaurant today.
The 23 flavours are really 23 ingredients, but what those 23 ingredients are is a closely guarded secret, similar to the ingredients that are used to make Coke have its flavour. There is an urban legend that claims at least part of the flavour is from prune juice but that is not true. Dr Pepper may not tell people what is in it, but they will admit that prune juice is not one of the ingredients.
There is cherry and vanilla Dr Pepper, but those flavours are added on top of the original flavours.
You can try asking Dr Pepper themselves, but I doubt you’ll have much luck.
http://www.drpepper.com/
