[Update on the subject of lead toxicology].

In the past 10-15 years increasing attention has been paid to subclinical effects and to early or subtle health effects induced by lead (Pb) exposure. They form a continuum with classical clinical effects differing from them only for their degree. Accurate knowledge has been acquired on the effects of low level Pb exposure, especially concerning the effects on the nervous system, the cardiovascular system, the endocrine and immune system, on heme containing enzymes, and on reproductive function. The question of a possible mutagenic and carcinogenic action of Pb on humans is still open. Many of the above mentioned effects have been observed for blood lead (PbB) levels below the current limits proposed for workers and the general population. In addition, for certain effects, like those on heme, central nervous system, and blood pressure, it has not been possible to establish a clear threshold value. A critical evaluation of the current prevention models appears to be appropriate to eliminate the dose-dependent effects occurring in highly exposed groups and to reduce, as much as possible, the effects without threshold in the general population.