Thank you for being concerned about your friend, and I, with you, hope that all is well. The best thing to do is to discuss this your doctor
. Obviously, there are many common foods that contain products that are not healthy when taken in large quantities. To some degree, this can be said about most of the processed foods that we eat in this century. Red licorice obviously contains many additives and coloring that our bodies may or may not be used to. Perhaps most importantly, red licorice contains large amounts of sugar, which can cause problems either short or long term with blood sugar (please note that red licorice, in this regard, is just the same as any other candy, and should thus be eaten in moderation--in other words, it's not just red licorice that you should avoid eating too much of, but any other snack or candy). As for any special additive or ingredient in red licorice that may have led to your friend's current problem, I am not aware of any in most red licorice. You would do best to speak with your doctor and perhaps even the manufacturer of red licorice. Your doctor will be able to help you best, so please speak with your doctor.