Usually the small amount present in any of these items will not cause any side effects. Some clear sodas, such as Mountain Dew, contain more caffeine than a cup of coffee. Some soft drinks have a large amount of added caffeine. Caffeine is present in most soft drinks. Soft drinks that do not have caffeine are usually labeled caffeine free.
Caffeine withdrawal can result in flu-like symptoms, as well as headaches.
Caffeine withdrawal can be bothersome, although it is not life threatening. Many people report symptoms if they miss their morning cup of coffee, or attempt to stop drinking caffeine. The headaches can be strong, and last for anywhere from a few days to weeks. The flu-like symptoms usually resolve within a few days. Weaning yourself slowly will help to avoid these symptoms.