Twenty "normal" (non-hyperactive) preschool children (9 girls, 11 boys) and 6 schoolage boys were maintained on a low sucrose diet for two weeks. During the second week, subjects were randomly assigned to one of two treatments (drink sweetened with either sucrose or aspartame). Cherry-flavored drinks mixed in a distilled water base were given daily. Subjects in the sucrose group received 3.4 g sucrose per kilogram of body weight, mixed to a concentration of 25 g per 100 ml. Subjects in the aspartame group received the same cherry-flavored drink mixed to a concentration of 8 g of aspartame per 100 ml of drink. A simple reaction-time task measured attention and alertness three times during the study: (1) prior to the low sucrose diet; (2) after one week of the low sucrose diet; (3) after one week of receiving the treatment. The dependent variable was the difference between reaction time at time 3 (after treatment) and time 2 (at the end of one week of a low sucrose diet). An ANCOVA (2 levels of treatment, age as covariate) revealed no significant difference in the mean reaction times of the subjects in the sucrose and aspartame groups. However, the variance in reaction times for those in the sucrose treatment group was significantly greater (p̱< .03) than for those in the aspartame group. / Master of Science