This study was conducted to determine the effects and the differences, if any, resulting from the ingestion of aspartame (sweetener) versus sucrose. A 13‐wk, double‐blind study was conducted using 726 apparently healthy children and adolescents as panelists. Individuals were randomly assigned in a double‐blind design to aspartame or sucrose in each of five age groups; dosage levels were assigned according to age and weight groups. Physical examinations and special eye examinations were performed at the beginning and end of the study. Other parameters determined including laboratory tests of liver and renal function, hematologic status, and plasma levels of phenylalanine and tyrosine.