(1) A hypothesis has been proposed that artificial food colourings have a role in exacerbating hyperactive behavior in children; (2) A placebo-controlled, double-blind, crossover clinical study in 297 children representative of the general population showed higher hyperactivity scores during the periods when they were ingesting food colourings; (3) A meta-analysis of 15 double-blind clinical trials that evaluated artificial food colouring in children already considered to be hyperactive showed an increase in their hyperactive behavior; (4) In practice, even though the mechanism underlying this phenomenon has not be elucidated, these data suggest that it is best to avoid exposing children to artificial food coloring.