Aluminum is the third most abundant element in the Earth's crust, after oxygen and silicon. Humans are exposed to naturally occurring aluminum through direct contact with soil and air, as well as through the consumption of food grown in soil and spring water. Furthermore, it is a metal used in many fields (construction, transportation, food processing, packaging, pharmaceuticals, surgery, cosmetics, and drinking water treatment). Does this element, which is ubiquitous in our environment, pose a danger to humans? Long considered safe for humans, particularly due to its very low absorption by the body, numerous studies now show that aluminum can be toxic. However, determining the health impact of human exposure to aluminum remains extremely difficult and is a source of much controversy. Following the publication in 2000 of the results of an Inserm (U330) study highlighting an increased risk of dementia, particularly Alzheimer’s disease, among people living in areas where the distributed water is high in aluminum, the Directorate General for Health referred the matter to the Institute for Public Health Surveillance (InVS) and the French Agency for Food Safety (Afssa). It sought a critical analysis of the risks associated with aluminum consumption in France and, if necessary, recommendations to improve knowledge and revise regulatory provisions (water and food). Since the French Health Products Safety Agency (Afssaps) had also initiated a review of aluminum in health products—a first in France—the InVS, Afssa, and Afssaps joined forces to organize a national expert assessment. This report presents a summary and detailed analysis of the available epidemiological data used to characterize the risks of aluminum to humans. More than 270 publications from the 1960s to the present have been reviewed by a panel of experts with diverse expertise (epidemiology, neurology, toxicology, drug evaluation). These experts weighed in on the proven effects of aluminum and on those—such as Alzheimer’s disease—for which aluminum cannot yet be held responsible. The conditions under which aluminum’s toxic effects occur and the difficulties in interpretation are discussed in depth. The report concludes with a series of proposals that were submitted to toxicologists and specialists in water, food, and health products. Most of these recommendations were amended and included in the InVS-Afssa-Afssaps summary report published in November 2003. (R.A.)