A Perth mum has issued a stark warning to Aussies after uncovering a “horror” sight inside a household item used daily.

Liesl, who works as a professional cleaner in Perth’s south, said a teeth-cleaning session with her six-year-old daughter on Monday evening quickly turned sour when she discovered a “weird brown substance” seeping from the toothbrush.

“I noticed the brown was also inside the crevice, so I started picking at it with a toothpick,” Liesl told PerthNow about the discovery.

“(The substance) just kept coming and coming, just more and more.”

Deciding the brush was no longer safe for her child, the Perth cleaner curiously took a hammer to the tool — and what she found inside the commonly used product left her “absolutely disgusted”.

“OH MY GOD 🤢 It was absolutely stuffed with mould and GUNK,” she shared in a post to her 5200 Instagram followers.

“The head is no more than a month old, yet my 6 year old’s brush has ended up packed with mould which she has been putting in her mouth.

“Take this as a warning: check your electric toothbrush.”

Her post about the vile discovery was flooded with comments from fellow Aussies complaining that they had also experienced similar mould build-up inside their Oral B electric toothbrushes.

“I notice my kids ones get like this within a month too! So gross,” one mum commented.

Another Perth mum wrote: “That’s exactly why I stopped using the Oral B toothbrush — all of the heads have that!”

“I changed my kids from the Oral B ones for this reason, (it) happened multiple times no matter how much they were rinsed and cleaned after use,” a third parent chimed in.

A phoo of the brown gunk found inside Liesl’s daughter’s toothbrush. Camera IconA phoo of the brown gunk found inside Liesl’s daughter’s toothbrush. Credit: @cleanfreakcleaningco

Liesl told PerthNow that she believes a design flaw with the Oral B electric brushes allows bacteria and mould to invade the tool easier than other toothbrushes.

“We’ve been rinsing it and maintaining it but it’s the design that’s the issue, in my opinion, because there are holes in the front and the back of the brush,” she said.

“The holes are obviously where the moisture is getting in and no amount of shaking is going to get it back out due to the design.

“A lot of people commented on my post to say they made the switch because of this design flaw, we’re back to using the regular manual toothbrushes for now.”

Another image showing how deep the mystery substance has gone inside the brush. Camera IconAnother image showing how deep the mystery substance has gone inside the brush. Credit: @cleanfreakcleaningco

Liesl told PerthNow that she made the choice to share the post publicly to raise awareness among other parents about the dangers of electric toothbrushes.

“I didn’t have a clue (this could happen) unless I had a look and noticed the brown in the toothbrush holes,” she said.

“Some people aren’t that aware or vigilant and I would just hate for them to miss that and allow their kids to be using a toothbrush that could have mould inside.

“That’s just too dangerous.”

PerthNow has contacted Oral B owners P&G for comment.