A consumer watchdog in the UK says some slimes marketed as kids' toys have potentially dangerous levels of a chemical which can cause vomiting and cramps.
One, which is sold in New Zealand, had more than four times the permitted level of boron.
Gooey slippery slime is a hit with children but the watchdog known as Which? says ones that have higher than the 300 milligrams of boron per kilogram permitted could be harmful.
Which? Spokesperson Nicky Stockford says parents are in a tricky situation regarding information on the products.
"There needs to be much closer market surveillance at government level, and retailers need to start acting - and manufacturers as well - to make sure unsafe products aren't reaching peoples' homes" he says.
The main culprit, Jupiter Juice, has four times the EU's permitted level of boron, and can be bought in stores and online in New Zealand.
However a local expert says the offending slimes will only be harmful if a huge amount is ingested.
Slime expert Bill Alexander Denny says the ingredient borax is found in most detergents, so parents shouldn't be too worried.
"It's relatively non-toxic, so if you swallowed a lot of it you might throw up - but it's unlikely that you'll be dangerously ill," Mr Denny says.
"Play with it safely - don't eat it, wash up afterwards, and have fun," adds another.
In a statement, Trading Standards says it will be investigating the matter "to more fully understand the composition of slime type products".
It says it will look at the "risks involved with boron exposure" and "whether mitigations are required".
Currently, the only standard children's toys in New Zealand is for lead levels.