Effect of certified artificial food coloring on learning and activity level in rats.

Chronic oral administration of a formula consisting of seven FD&C certified artificial food dyes, given in 0, 2.0, and 5.0 mg/kg doses, failed to produce changes in measures of physical or motor development in rat pups. Two learning tasks, one given during development and the other at maturity, also revealed no differences among groups. In addition, two activity level measures, time-sampled observations and the open field task, were taken on five occasions. These measures also failed to demonstrate any effects of food coloring. Although food dyes may have toxic effects at higher dose levels or under unusual dietary or environmental conditions, these results suggest that orally ingested low doses do not reliably elicit behavioral changes.