With the recommendation of the World Health Organization (WHO) to reduce the sugar consumption of children and adults to less than 10% of the total energy intake, many people turned to sweeteners. Aspartame (E951), an artificial sweetener, is synthesized from L-phenylalanine or methyl ester of L-phenylalanine with L-aspartic acid. It is an amphoteric dipeptide composed of aspartic acid and phenylalanine. Apart from chemical peptide synthesis, aspartame can also be synthesized enzymatically commercially. 1 gr of it gives 4 Kcal energy. The taste perception of aspartame appears delayed and lasts a long time. Since it is not heat resistant during cooking, it can only be used as a sweetener in cold drinks and food, coffee, tea. Although there were some scientific objections after the introduction of aspartame to the market, animal and human experiments and investigations started to increase. In another study; Consumption of 40, 75, 500 mg/kg/day aspartame have increased oxidative stress parameters and has been reported to damage liver antioxidant capacity. Also, in some other studies in which negative effects on experimental animals were discussed, 250, 500, 1000 mg/kg/day aspartame consumption was found to significantly increase the liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Besides, studies showing that aspartame does not have negative effects on health, 240 mg/kg/day aspartame consumption did not make a significant difference in alanine aminotransferase (ALT) value, and there was no significant difference between the groups in fasting blood glucose with 4% aspartame solution daily consumption. On the other hand, studies on aspartame toxicity also have conflicting results. Some studies using in vivo and in vitro tests have shown that aspartame does not cause genotoxicity, DNA damage, and mutagenesis, but does stimulate chromosome aberrations and micronucleus formation. Many studies have been done to show the safety of aspartame. The European Food Safety Authority stated in its 2013 re-evaluation that aspartame is safe for human consumption at current exposure levels. In a review evaluating the data obtained from aspartame studies, it is supported that aspartame is a safe sweetener when used within the recommended dose limits. For aspartame, this value (ADI) has been recommended as 40 mg/kg body weight/day. Considering its association with age, gender, personal metabolism, and metabolic diseases, it was concluded that the use of aspartame is safe, with the fact that it has some harmful effects depending on the exposure time and dose.