According to a 2007 safety evaluation, the weight of existing evidence indicates that aspartame is safe at current levels of consumption as a non-nutritive sweetener.<ref name=CritReview>{{cite journal |author=Magnuson BA, Burdock GA, Doull J, ''et al'' |title=Aspartame: a safety evaluation based on current use levels, regulations, and toxicological and epidemiological studies |journal=Crit. Rev. Toxicol. |volume=37 |issue=8 |pages=629–727 |year=2007 |pmid=17828671 |doi=10.1080/10408440701516184 |url=}}</ref> The [[artificial sweetener]] [[aspartame]] has been the subject of public [[controversy]] regarding its safety since 1974.<ref name=GAO87/><ref>{{cite news |url=http://pqasb.pqarchiver.com/washingtonpost_historical/access/125899752.html?dids=125899752:125899752&FMT=ABS&FMTS=ABS:FT| publisher= ''[[Washington Post]]''|title=Controversy Surrounds Sweetener|first=Carole | last=Sugarman|date=1983-07-03|accessdate = 2008-11-25|pages=D1-2}}</ref> Some scientific studies, combined with allegations of [[Conflict of interest|conflicts of interest]] in the approval process have been the focus of vocal activism and conspiracy theories regarding the possible risks of aspartame.{{fact}}

The [[conspiracy theory|conspiracy theories]], claims of aspartame dangers, and the source of those claims have been the subject of critical examination.<ref name=MAN_Markle>[http://www.media-awareness.ca/english/resources/educational/teaching_backgrounders/internet/decon_web_pages.cfm Deconstructing Web Pages] - An exercise deconstructing a web page to determine its credibility as a source of information, using the aspartame controversy as the example.</ref> In 1987, the US Government Accountability Office concluded that the food additive approval process had been followed for aspartame.<ref name=GAO87>GAO 1987. [http://www.gao.gov/docdblite/info.php?rptno=HRD-87-46 "Food Additive Approval Process Followed for Aspartame"] United States General Accounting Office, GAO/HRD-87-46, June 18, 1987</ref> Based on government research reviews and recommendations from advisory bodies such as the [[European Commission]]’s Scientific Committee on Food and the [[Joint FAO/WHO Expert Committee on Food Additives]], aspartame has been found to be safe for human consumption by more than ninety countries world-wide.<ref name="Health Canada">[[Health Canada]]: {{cite web |url=http://www.hc-sc.gc.ca/fn-an/securit/addit/sweeten-edulcor/aspartame-eng.php |title=Aspartame - Artificial Sweeteners |accessdate=2008-11-08}}</ref><ref name=FSANZ>[[Food Standards Australia New Zealand]]: {{cite web |url=http://www.foodstandards.gov.au/newsroom/factsheets/factsheets2007/aspartameseptember203703.cfm |title=Food Standards Australia New Zealand: Aspartame (September 2007) |accessdate=2008-11-08}}</ref> In 1999 Jon Henkel reported that the [[U.S. Food and Drug Administration]] scientists believe that the safety of aspartame is "clear cut" and "one of the most thoroughly tested and studied food additives the agency has ever approved."<ref>[http://www.fda.gov/fdac/features/1999/699_sugar.html FDA Consumer magazine November - December 1999]</ref>However, former FDA scientists have publicly stated the dangers of aspartame consumption.<ref>Testimony of Dr Jacqueline Verrett, FDA Toxicologist before the US Senate Committee on Labor and Human Resources, (November 3, 1987).</ref><ref>Eating May Be Hazardous To Your Health - The Case Against Food Additives by J. Verrett J.carper, published by Simon & Schuster</ref><ref>Statement from Dr. Adrian Gross, Former FDA Investigator and Scientist, Aspartame Safety Act," Congressional Record, Volume 131, No. 106, August 1, 1985, page S10835-S10840.</ref> As of 2008, disagreement still exists among scientists over aspartame's role in certain mental disorders, compromised learning, and emotional functioning,<ref name=pmid17684524>{{cite journal |author=Humphries P, Pretorius E, Naudé H |title=Direct and indirect cellular effects of aspartame on the brain |journal=European Journal of Clinical Nutrition |volume=62 |issue=4 |pages=451–62 |year=2008 |month=April |pmid=17684524 |doi=10.1038/sj.ejcn.1602866 |url=}}</ref> as well as different forms of cancer<ref name=pmid16507461/>

Controversy surrounding the approval process led Senator [[Howard M. Metzenbaum]] to request a report by the [[Government Accountability Office]] (GAO) of aspartame's approval. The GAO concluded that protocol was followed, although it did not analyze aspartame's safety. The GAO provided a timeline of the events.<ref name=GAO87/>{{rp|13}} Aspartame was originally approved for use in dry foods in 1974 by then Commissioner [[Alexander Schmidt]] after review by the FDA's Center for Food Safety and Applied Nutrition, but G.D. Searle, its creator, was not allowed to market it until 1981 because of questions surrounding the reliability of its data. Searle initially submitted 168 studies<ref name=GAO87/>{{rp|20}} on aspartame, including 7 animal studies which were considered crucial by the FDA and one controversial study on whether aspartame caused seizures in monkeys.<ref name=GAO87/>{{rp|21}} Soon after aspartame was approved, three objections were filed, including one by the scientist [[John Olney]] and another by James Turner, a public-interest lawyer who partnered with Olney.<ref>Cockburn A. (2007). ''Rumseld'', [http://books.google.com/books?id=2Di2D4R25bEC&printsec=frontcover#PPA63,M1 pp. 63-4]. Simon and Schuster.</ref> A Public Board of Inquiry was planned, but delayed because the FDA noticed problems with Searle's laboratory practices and inaccuracies in its data on two other drugs. The FDA Commissioner appointed an FDA task force to investigate 3 of Searle's studies while the Universities Associated for Research and Education in Pathology (UAREP) examined 12 others. Errors were found, but CFSAN concluded that they were not significant. In 1980 the Public Board of Inquiry (PBOI) of three university scientists (one from each list provided by CFSAN, Searle, and Olney) heard John Olney's objections, and responded by revoking aspartame's approval because of concerns over the reliability of two of the three crucial studies related to brain cancer.<ref name=GAO87/>{{rp|38}} In 1981 FDA Commissioner [[Arthur Hull Hayes]] set up another panel, which did not reach consensus on aspartame's safety, but in 1981 the Commissioner overturned the PBOI's decision and approved aspartame. Hayes justified his approval through the results of a Japanese brain tumor study, the results of which, the PBOI chairman later said, would have resulted in an "unqualified approval" from the PBOI panel.<ref name=FDA1996>[http://www.fda.gov/bbs/topics/answers/ans00772.html FDA Statement on Aspartame], November 18, 1996</ref> Several objections followed, but all were denied.<ref name=GAO87/>{{rp|13}} In November 1983, Hayes left the FDA and joined [[G. D. Searle & Company|Searle]]'s public-relations firm [[Burson-Marsteller]] as senior medical advisor,<ref name=GAO86>GAO 1986. [http://archive.gao.gov/d4t4/130780.pdf "Six Former HHS Employees' Involvement in Aspartame's Approval."] United States General Accounting Office, GAO/HRD-86-109BR, July 1986.</ref> a decision which would fuel conspiracy theories.

As a result of the Ramazzini study, for the first time CSPI (Center For Science in the Public Interest) downgraded aspartame on its online Chemical Cuisine directory from a "use caution" rating to "everyone should avoid."<ref>http://www.cspinet.org/new/200706251.html</ref><ref>http://www.cspinet.org/reports/chemcuisine.htm</ref>