Aspartame is a chemical consisting of aspartic acid, phenylalanine and methyl alcohol. It is an artifical sweetener to which a few people are sensitive but never to the extent of peanuts or wheat. It will decompose to form aspartic acid and phenylalanine which are amino acids that are essential to your health. It also forms methyl alcohol but you get more methanol eating an orange than drinking a can of soda containing aspartame. It has never been shown to be dangerous to people. Some people try to say that pilots have been told to never ingest aspartame or they will be fired. That is simply a lie. I know a tremendous amount about aspartame because I spent 4 years studying it's kinetic decomposition. I doubt the other people reporting about aspartme here really know what they are taliking about.
The government has shown that drink soft drinks containing aspartame is not dangerous unless it is consumed in very large quantities.