They make bath-time fun for little ones – but rubber ducks could be concealing a deadly health risk.
The toys are teeming with bacteria which could cause serious illness or even death, researchers warn.
Bugs found inside ducks and other plastic toys which squirt water included Legionella and drug-resistant superbugs.
The warm and humid environment in bathrooms is an ideal breeding ground with ‘dense growths of bacteria and fungi’ building up inside toys, the Swiss study said.
Children who play with rubber ducks risk suffering eye, ear or stomach infections, it warned. Adults supervising or playing with youngsters could also be vulnerable, the academics added. They experimented on toys over 11 weeks, simulating bathtimes and exposing the ducks to dirty water, soap, sweat and urine.
Bath toys from real households were also examined by the team at the Swiss Federal Institute of Aquatic Science and Technology.
They found four out of five contained potentially dangerous bugs, with 5 to 75million bacterial cells per square centimetre on the inner surfaces. The plastic used to make the ducks also helped to nourish bugs by releasing edible carbon compounds, they added.