Here's some good news for parents who constantly worry about their kids' hygiene after they spend time in the play ground - eating dirt could actually make your child smarter.
A new study has shown the positive side of soil-borne bacteria that is likely to be inhaled when children are playing outside.
Scientists discovered that mice that were fed the dirt bacteria Mycobacterium vaccae navigated complex mazes twice as fast as those which were not.
The research was welcomed by Kidsafe NSW Playground Advisory Unit program manager Kate Fraser as another reason kids should be encouraged to get outside and get dirty.
"Over the past few years terms like 'cotton wool kids' and 'helicopter parents' are becoming really common," the Courier Mail quoted Fraser as saying.
"So we thought it was time to air the laundry on what's happening with our play spaces and make sure we are offering kids challenges.
"We need to make playgrounds safe, but also offer a certain amount of risk and controlled risk. It's a real balancing act."
It is believed the bacteria increases levels of serotonin, reduces anxiety and may also stimulate growth in certain neurons in the brain.
Fraser said that while playing in the dirt was great, parents should take care around potting mix, which can contain harmful bacteria.
"But as long as safety directions are followed, that can be a great learning experience, too," she said.
The study has been published in the current issue of Kidsafe NSW's playgrounds newsletter.