There are calls for toy slime to be removed from sale ahead of Christmas.
Which? found almost half of them - in high street shops and online firms - failed EU safety limits for the potentially dangerous chemical.
The BBC says the UK consumer group tested Goobands Frootiputti slime and found it contained four times the EU safety standard limit for a chemical called boron.
High exposure to boron can make people sick, impair their fertility and cause harm to unborn children, according to the European Commission.
The consumer watchdog says it's informed manufacturers and retailers.
