In response to a congressional request, GAO reviewed the Food and Drug Administration's (FDA) Center for Food Safety and Applied Nutrition's (CFSAN) process for approving aspartame, specifically its: (1) review of the scientific issues raised concerning the aspartame studies; and (2) monitoring of current safety concerns.

GAO found that the: (1) firm that developed aspartame submitted nearly 170 studies supporting its safety; and (2) studies that CFSAN considered crucial for approval met FDA requirements. GAO also found that CFSAN: (1) adequately followed its food additive approval process by reviewing all of the manufacturer's aspartame studies, holding a public board of inquiry to discuss safety issues, and forming an advisory panel; (2) had an outside group of pathologists review the crucial studies; and (3) used the studies to establish a safe level for long-term consumption before approving aspartame for marketing. In addition, GAO found that: (1) there was no evidence of pressure on the former FDA Commissioner to approve aspartame after a board of inquiry revoked a 1974 approval and decided that additional research was necessary; (2) three members of an advisory panel did not believe that the studies conclusively showed that aspartame would not cause brain tumors; (3) 12 of the 69 scientists responding to its questionnaire expressed major concerns about aspartame safety; and (4) there are over 70 completed, ongoing, and planned studies of aspartame effects on neurological behavior, children, and pregnant women. GAO believes that CFSAN research and monitoring of adverse aspartame reactions should provide a basis for determining the need for any future regulatory actions.