Triclosan promotes antibiotic resistance
Microbes have turned our pharmaceutical weapons into allies. This year, triclosan, an antimicrobial agent, topped the list of chemical traitors, aiding rather than deterring germs.
Leaked from products such as toothpaste and hand soap, low doses of triclosan promote drug resistance in germs that cause difficult-to-treat infections. In the environment, the chemical can disrupt hormone regulation in some animals, such as fish. (Data are lacking on health effects in humans.)