The American Council on Science and Health

"Anecdotal accounts, however compelling, do not constitute scientific evidence of a cause-and-effect relationship. Millions of people experience unpleasant physical symptoms. It is natural for an individual to look for a cause for his or her physical discomfort, and aspartame is an obvious, well-publicised candidate. However, the mere fact that a person consumed this sweetener (aspartame) and experienced some kind of problem does not mean that aspartame caused the problem. This situation could just as easily be a coincidence. People who are concerned about the safety of aspartame can be reassured by the results of the Centers' for Disease Control recent evaluation of complaints about the sweetener. The CDC said that the complaints do not provide evidence for the existence of serious, widespread adverse health consequences from using aspartame".