Researchers at Johns Hopkins Children’s Centre in the U.S. analyzed urine from 860 youths age 6 to 18.
The scientists found that children showing high levels of anti-bacterial chemicals such as triclosan also had roughly double the risk of food and environmental allergies.
University of B.C. microbiologist Brett Finlay said he isn't surprised by the findings, because anti-bacterials kill off useful microbes.
"So if you don't see them as a kid, later in life you react to them and you get things like allergies and asthma."
Finlay said people should use anti-bacterials in strict moderation. "We call it the hygiene hypothesis - we just live too clean these days."
About six per cent of North American children now have environmental or food allergies.
"All these auto-immune diseases, such as asthma and allergies and multiple sclerosis, inflammatory diseases, these are all going through the roof in our society,” said Finlay. “In places like Africa, where it's still a more dirty world, if you will ... it hasn't changed."
The Canadian Cosmetic, Toiletry and Fragrance Association, was asked for comment Thursday, but said it needed more time to analyze the study’s results.