Background: Aspartame is one of the most widely used artificial sweeteners in over 90 countries worldwide in over 6000 products, including carbonated and powdered soft drinks, hot chocolate, chewinggum, candy, desserts, yogurt, and tabletop sweeteners, as well as some pharmaceutical products like vitamins and sugar-free cough drops. Aspartame has been shown to induce oxidative stress and lipid peroxidation; most serious effects result from chronic exposure due to these effects. Also it shows organ and species toxicity with relation to the liver, kidney, brain, testis and other organs. The aim of this study is to spotlight on aspartame, the most widely used artificial sweetener regarding benefits and Hazards. This essay was conducted by reviewing the literature, researches, and textbooks dealing with aspartame. Conclusion: We found that aspartame is a good& beneficial artificial sweetener; FDA approved a safe daily dosage of 40 mg/kg/ day regarding diabetes and obesity. Harmful if used in larger doses regarding neurobehavioral, hepatic, testicular and other organ dysfunction, however it has no effects on breastfeeding or carcinogenic effects.Therfore, the role of physicians is to adjust the dose of aspartame to that which approved by FDA and do more clinical studies to detect more benefits and hazards.