The US Food and Drug Administration has banned 19 active ingredients in antibacterial soaps — including the hotly debated chemicals triclosan and triclocarban. The rule is meant to help curb antibiotic-resistance and some other effects of the chemicals, including hormonal interference.

The ruling is the FDA's final say in an ongoing debate about whether triclosan and 18 other antimicrobial ingredients actually work and are safe to use. In 2013, the FDA issued a proposed rule requiring manufacturers who wanted to keep using these ingredients to show evidence that they were safe for repeated, long-term use — and that they worked better than regular soap and water. "Antibacterial hand and body wash manufacturers did not provide the necessary data to establish safety and effectiveness for the 19 active ingredients addressed in this final rulemaking," the FDA said in its statement.

Triclosan is a common ingredient in antibacterial liquid soaps and an environmental contaminant that is incompletely eliminated in water treatment plants. When bacteria become resistant to triclosan, they may also become resistant to several other antimicrobials, according to a 2014 literature review in the journal Environmental Science and Technology. What this means for the growing threat of antibiotic resistance is still unclear. Triclosan may also affect thyroid and reproductive hormones according to laboratory studies in rodents and frogs. Laboratory studies suggest that it might also also weaken skeletal and heart muscle.

"Consumers may think antibacterial washes are more effective at preventing the spread of germs, but we have no scientific evidence that they are any better than plain soap and water," Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, said in a news release. "In fact, some data suggests that antibacterial ingredients may do more harm than good over the long-term."

The good news, for the germaphobes out there, is that plain old soap works to prevent the spread of disease.