Environmental hazards in milk and infant nutrition.

Epidemiologic studies have provided much of the knowledge concerning adverse side effects of exposure to drugs and other xenobiotics transmitted via breast milk. Adverse effects can be immediate and usually recognizable or long-term and difficult to define. Acute effects may be due to individual idiosyncrasy, allergic reaction, or manifestation of acute toxicity. We need further human clinical investigations to determine actual dosing to nursing infants and to ascertain the existence of subtle and presently unrecognized long-term effects.