Over 550 people have phoned the Independent Television Commission (ITC) because they didn't like it.
An ITC spokesperson told CBBC Newsround's website about a quarter of the complaints were from mums and dads.
It upset their kids so much, many are now afraid of their pet dogs.
In the ad, a man wakes up on his sofa gagging. Furry paws appear from his mouth and out jumps a snarling, mongrel-like mutt!
He takes a mint and the dog disappears. It's supposed to show gum can get rid of ponging "dog breath".
Clever
It's all done using clever computer technology. But some say it looks so real, it has actually made them puke.
A spokesperson for the gum makers, The Wrigley Company, told us: "It is not, nor has it ever been, our intention to upset anyone by our adverts."
They have now agreed to only show the ad after the 9pm watershed, when kids aren't supposed to be watching.
In 1998, a Levis ad about a bored hamster had 544 complaints. But this dog breath one beats that record.
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